If this is a dumb question, forgive me. I have a small amount of experience with C#, but not to this degree yet.
I have a series of images that I want to put into a grid with space around each image, also text beneath them and I want them to be clickable, so when they're clicked they hilite, and double click runs an event. The best example I have for this is the user interface of the program ACDSee. I've googled this for hours, and haven't come up with anything applicable. Is this difficult or simple? Can anyone give me an example, or point me in the right direction?
Cheers.
It doesn't seem to be very difficult. I would suggest the following steps:
Add a new "User Control" to your project for image thumbnails. It can contain a docked PictureBox and a Label or LinkLabel at its bottom.
For the space around each thumbnail simply play with the Padding property of the user control.
For the so called grid that is going to hold the thumbnails, use a FlowLayoutPanel, and simply add instances of the above mentioned user-control to this panel.
For visual representation of being selected, change the background color of the user-control instance to blue (for example), and back to control-face when deselected. It is recommended to implement an IsSelected property for the user-control as well.
To emulate thumbnail selection, handle the Click event of the user-control and assign the events for all thumbnail instances to a single event-handler method. Store a global reference to the already selected thumbnail, name it e.g., SelectedThumbnail initialized with null. In the event-handler body compare the sender with the global SelectedThumbnail, and update it if required. If the user-control associated with the sender is not selected (i.e., its background is not blue, or IsSelected is false) make it selected, or change its background. Otherwise change the background to its default color (e.g., control-face).
The Click event handler body looks something like this:
MyThumbnailControl ctrl = sender as MyThumbnailControl;
if(ctrl == null) return;
if(ctrl == SelectedThumbnail) return; // selected again
if(ctrl != SelectedThumbnail)
{
ctrl.IsSelected = true;
ctrl.BackColor = Color.Blue;
// it's better to set the back-color in the IsSelected property setter, not here
SelectedThumbnail.IsSelected = false;
SelectedThumbnail.BackColor = Color.Control;
SelectedThumbnail = ctrl; // important part
}
It's also recommended that all thumbnail instances that are going to be added to the so-called grid, be referenced in a separate array too. Therefore changing selection with arrow-keys would be possible with simple index calculations.
Further Notes: I assumed that the user-control that is to be created is named MyThumbnailControl, just a random name to refer to that control. When you create a new user-control, the wizard generates a class for you with your desired name (e.g., MyThumbnailControl), you can define a property inside it named IsSelected and implement its getter and setter. See this for a tutorial. After defining the user-control you can instantiate instances from its corresponding class. Also by global reference, I meant a variable at the form (or any parent control) level. To keep it simple we can add a reference of the selected thumbnail in the form that is going to hold the grid and thumbnails: MyThumbnailControl selectedThumb = null; or something like this in the body of the form.
Here is something, I just fixed you.
Create a C# project name CreateImageList and in the Form1 add the following 5 controls with their default name i.e. Panel1, PictureBox1, Label1, Button1, Button2:
How it works:
When the page load it create an imageList objects and load all .jpg images from a folder you provide
ImageList Images are set into the PictureBox control and when user clicks "Button1" the picturebox shows next image in ImageList and when user clicks "Button2" the PictureBox shows previous image from ImageList.
The Label1 shows the currentImage counter from the ImageList Arrage. If you want to write something specific, you can create an array of text and sync with your image counter.
When user click on PictureBox the a border is create to show Picture highlighted
When user Double Click on PictureBox a MessageBox appears shows DoubleClick event.
Now, you can use the following code:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO;
namespace CreateImageList
{
public partial class Form1 : Form
{
private int currentImage = 0;
protected Graphics myGraphics;
ImageList iPicList = new ImageList();
public Form1()
{
InitializeComponent();
DirectoryInfo dirImages = new DirectoryInfo("C:\\2012");
iPicList.ImageSize = new Size(255, 255);
iPicList.TransparentColor = Color.White;
myGraphics = Graphics.FromHwnd(panel1.Handle);
foreach (FileInfo file in dirImages.GetFiles())
{
if (file.Extension == ".jpg")
{
Image myImage = Image.FromFile(file.FullName);
iPicList.Images.Add(myImage);
}
}
if (iPicList.Images.Empty != true)
{
panel1.Refresh();
currentImage = 0;
// Draw the image in the panel.
iPicList.Draw(myGraphics, 1, 1, currentImage);
// Show the image in the PictureBox.
pictureBox1.Image = iPicList.Images[currentImage];
label1.Text = "Image #" + currentImage;
}
}
private void showImage(int imgIndex)
{
// Draw the image in the panel.
iPicList.Draw(myGraphics, 1, 1, currentImage);
// Show the image in the PictureBox.
pictureBox1.Image = iPicList.Images[currentImage];
label1.Text = "image #" + currentImage;
panel1.Refresh();
}
private void button1_Click(object sender, EventArgs e)
{
if (iPicList.Images.Count - 1 > currentImage)
{
currentImage++;
}
else
{
currentImage = 0;
}
showImage(currentImage);
}
private void button2_Click(object sender, EventArgs e)
{
if (iPicList.Images.Count - 1 >= currentImage)
{
if (currentImage == 0)
currentImage = iPicList.Images.Count-1;
else
currentImage--;
}
else
{
currentImage = iPicList.Images.Count;
}
showImage(currentImage);
}
private void pictureBox1_DoubleClick(object sender, EventArgs e)
{
MessageBox.Show("Picture Box Double clicked");
}
private void pictureBox1_Click(object sender, EventArgs e)
{
panel1.Refresh();
myGraphics.DrawRectangle(Pens.Black, 0, 0, iPicList.Images[currentImage].Width + 1, iPicList.Images[currentImage].Height + 1);
pictureBox1.Image = iPicList.Images[currentImage];
}
}
}
The changes you need are:
Change the Following folder to a place where you have lots of jpg:
DirectoryInfo dirImages = new DirectoryInfo("C:\\2012");
Also if you are dealing with other kind of images, make change here:
if (file.Extension == ".jpg") // Change it to your image type.
If you don't want to use the the buttons to go up and down, you have several other options to host PictureBox control in scrollable Panel or list or something else.
Related
I am trying to create a Bitmap from a RichTextBox and set it as the background image for a panel, but unfortunately the text is not shown.
Bitmap l_bitmap = new Bitmap(m_control.Width, m_control.Height);
m_control.DrawToBitmap(l_bitmap, new Rectangle(0, 0, l_bitmap.Width, l_bitmap.Height));
m_panel.BackgroundImage = l_bitmap;
m_panel.Refresh();
m_control is my RichTextBox. When I debug, I can see that the control contains the text I wrote, but the bitmap just shows an empty RichTextBox.
I use the same code for other types of controls (Button, CheckBox, TextBox...). The text is shown with no problems.
Well you are trying to create a bitmap from the control. The text you put in there isn't the control, so it won't bother to chow it as bitmap. Try to create a picture from screen (like a screenshot).
Example:
Graphics gr = Graphics.FromImage(l_bitmap);
gr.CopyFromScreen(m_control.PointToScreen(Point.Empty), point.Empty, m_control.Size);
This will make a bitmap from your given points. This will additional show you the text.
EDIT
Maybe you can use this instead. In addition to your idea, I simply put a label onto my panel. (L for Label and P for Panel)
As you can see, the label is empty because I cleared the Text property. Now, when you click one of the buttons below the panel, it will update the label.Text propertie and there will be the text you gave the control.
Here is some example:
As you can see, the label shows the Name of the control. Completly custom as you can see on my source code:
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
public RichTextBox tmpRtf = new RichTextBox();
//Poor button name incoming...
private void button1_Click(object sender, EventArgs e)
{
if (tmpRtf == null)
tmpRtf = new RichTextBox();
//You can add any text here and it will be shown on the label.
this.tmpRtf.Text = "Richtextbox";
this.UpdatePanel(this.tmpRtf);
}
//Custom method to update the panel for any control. Can pobably be done way better than this, but hey.
private void UpdatePanel(object pControl)
{
//Checks if control is a rtf
if(pControl is RichTextBox)
{
//This is your code! Ay.
Bitmap l_bitmap = new Bitmap(this.panel1.Width / 2, this.panel1.Height / 2);
(pControl as RichTextBox).DrawToBitmap(l_bitmap, new Rectangle(0, 0, l_bitmap.Width, l_bitmap.Height));
this.tmpRtf.BackColor = Color.LightGray;
this.panel1.BackgroundImage = l_bitmap;
this.panel1.BackgroundImageLayout = ImageLayout.Center;
this.labelControlName.Text = this.tmpRtf.Text;
this.panel1.Refresh();
}
}
}
Its not possible to show text on a control thats not visualized. But you can build a workaround! Or, instead of taking a picture you can simply create the control on top of it, that will also show the Text and maybe the user can test it (e.g. click on buttons, look at the control behaviour).
Hopefully this is something to get you inspired that there are always more ways to accomplish.
I wonder if it's possible to customize my C# application (winforms) to get a better design, I made a PSD (photoshop document) so I can generate png jpeg... pictures if I need them.
Example of a form like the one I want :
Indeed as it was pointed out in the comments, it is easy to use WPF (indows Presentation Foundation) to achieve that result, but if you really need that it must be made in windows forms I can help you with that...
ControlBox and Border
It seens that your form does not have a control box (minimize, maximize and close buttons)
to achieve that you can set
form.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None
I'm not sure if that galaxy behind your form is part of the application so i'll be considering that it is not
To achieve that irregular shape of the form we have to do a workaround here
Irregular Shape of the Form
we are going to set a Color to TransparentKey, so everything in the form in that specific color will be transparent, like it does not exists (if you click in that part it will go into de desktop or whatever application you have behind in your form)
So let's use a specific color which we will probably dont use in the form
form.TransparencyKey = Color.FromArgb(111, 111, 111); //You can do it by the editor
So in order to make that white part we are going to use an Panel and a PictureBox outsite of the Panel trying to copy the shape of your image
Stylized Inputs
To make it easier and reusable I'm going to make a userControl in this one
the usercontrol will have
a Panel called HighLightPanel, its dock property will be set to Fill
a Panel called BackColorPanel, it will be inside the HighLightPanel
a PictureBox called InputPicture, its dock property will be set to Left, it will be inside BackColorPanel and its acessor will be public
a TextBox called TextBox, its dock property wil be set to fill, it will be inside BackColorPanel, the BorderStyle Property set to None, you should set the size and font you most desize in this one, I'm going to use Segoe UI; 15,75pt and its acessor will be public
Now we have to make some properties in our UserControl to make it work without work in other controls
First in the SizeChanged event of the HighLightPanel we will make the BackColorPanel be exacly two points smaller in every direction and its position to 1;1 so we can see the HighLightPanel
private void HighlightPanel_SizeChanged(object sender, EventArgs e)
{
this.BackColorPanel.Size = new Size(
HighlightPanel.Width - 2,
HighlightPanel.Height - 2);
}
Now we will create two propertys to handle the Highlight Color
public Color HighlightBorderColor { get; set; }
public Color NonHighlightBorderColor { get; set; }
And in the Enter and Leave Property of our TextBox we are going to change the HighlightPanel
private void TextBox_Enter(object sender, EventArgs e)
{
HighlightPanel.BackColor = HighlightBorderColor;
}
private void TextBox_Leave(object sender, EventArgs e)
{
HighlightPanel.BackColor = NonHighlightBorderColor;
}
So now every time the user enter the Input it will appear that the Input has an Border in the specified Color
Now to enhance its usability to developers we will make some wrappers in its controls to be easier change property of child controls in the editor
public Image InputImage
{
get { return InputPicture.Image; }
set { InputPicture.Image = value; }
}
public PictureBoxSizeMode InputImageLayout
{
get { return InputPicture.SizeMode; }
set { InputPicture.SizeMode = value; }
}
public char PasswordCharacter
{
get { return TextBox.PasswordChar; }
set { TextBox.PasswordChar = value; }
}
public bool ShowInputImage
{
get { return InputPicture.Visible; }
set { InputPicture.Visible = value; }
}
In the InputImage set the picture you want for the User and the Key
Insert the two controls in the position you like
Position of the Form
if you want your form to be moveable without the border you will have to use this snippet, it is more easy in WPF
#region MoveForm
Point LastPoint;
bool ShouldMove;
private void form_MouseDown(object sender, MouseEventArgs e)
{
LastPoint = e.Location;
ShouldMove = true;
this.TransparencyKey = Color.FromArgb(111, 111, 111);
}
private void form_MouseUp(object sender, MouseEventArgs e)
{
ShouldMove = false;
}
private void form_MouseMove(object sender, MouseEventArgs e)
{
if (ShouldMove)
{
this.Location = new Point(
this.Location.X - LastPoint.X + e.X,
this.Location.Y - LastPoint.Y + e.Y);
}
}
#endregion
If you need a lot of special graphics effects learning WPF will indeed be a sound investement.
If all you want is that login screen, it is trivial in Winforms and doesn't take any horrible hacks as you've been told..
this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
this.BackColor = System.Drawing.Color.LavenderBlush;
this.TransparencyKey = System.Drawing.Color.LavenderBlush;
this.ControlBox = false;
this.MaximizeBox = false;
this.MinimizeBox = false;
this.Text= "";
These seven lines are all it takes for a form to be transparent. I copied them from the Designer code; you can simply set the 7 Properties in the property grid.
Now add a panel, dock it to the bottom and give it the right color; add a picturebox and your other controls and you are set.
To create the two input groups you also need just a few regular controls and only a few simple lines of code:
You place one Panel, BorderStyle = FixedSingle; and add a Label and a TextBox to it. The Label has AutoSize = False; and both ImageAlign and TextAlign are set to MiddleLeft. You assign an image to the Label's Image and prefix the Text with enough blanks to not overlap. Obviously you should define a PasswordChar for the 2nd TextBox. Now all you need is to script the Enter and Leave events to change the BackColor of the respective Panels between, say SystemColors.Control and SystemColors.MenuHighlight. Size the Labels to almost fill the Panels and you are done. Less code than the WPF version, I'd bet.
If you need such input an controls again and again, simply create Usercontrols for each type you need!
Here is an example of the limits you will hit: Wouldn't it be nice to add a dropshadow effect to the image? It is doable in Winforms. But it would involve painting that effect; this would take at least 15 or 20 lines of involved code instead of simply turning the effect on with (estimated) 1-3 simple lines.
Do you need any nice hover effects? Not easy, to say the least..
These limits will be all over the place, so it really depends on how fancy your requirements will get.
Maybe you should use this example as a starter to compare the two techniques and to warm you up to WPF?
I have a C# Form application that has a TabControl in the main form. This TabControl is used to display multilple TabPages that contain a CustomControl. This CustomControl is just a Panel with a few buttons and a PictureBox.
Here is a picture of my app when it starts up. As you can see the tab control (the white area) is empty:
If the user clicks the "Add Image" button they are presented with an OpenFileDialog to select the image then the addImage method is called with the selected file:
private void doAddImage()
{
OpenFileDialog openFileDialog = new OpenFileDialog();
openFileDialog.Filter = Constants.Global.IMAGE_FILE_FILTER();
if (openFileDialog.ShowDialog() == System.Windows.Forms.DialogResult.OK)
{
string imageFileName = openFileDialog.FileName;
addImage(imageFileName);
}
}
private void addImage(string imageFileName)
{
// Create a new bitmap and image preview custom control. Then create a new tab
// page and add the custom control to the tab page.
Bitmap bitMap = new Bitmap(imageFileName);
ImagePreviewCustomControl previewControl = new ImagePreviewCustomControl(bitMap);
previewControl.Dock = DockStyle.Fill;
TabPage tabPage = new TabPage(Path.GetFileNameWithoutExtension(imageFileName));
tabPage.Controls.Add(previewControl);
// Insert the new tab page to the right of the currently selected tab page
int selectedTabIndex = imagesTabControl.SelectedIndex;
imagesTabControl.TabPages.Insert(selectedTabIndex + 1, tabPage);
imagesTabControl.SelectedIndex = selectedTabIndex + 1;
}
As you can see, in the addImage method I create the Bitmap, CustomControl, and TabPage and then insert it into the TabControl.
I start my application, click the "Add Image" button, everything works just fine.
Here is a picture with a tab page added:
While I am testing my app I don't want to have to add an image manually using the OpenFileDialog every time so in my constructor I just call addImage with some fixed image file name that I want to test with:
public ImageViewerApp()
{
InitializeComponent();
addImage(#"C:\MyImages\Calculator-3-icon.png");
}
The problem I am having is that when I try to add the image in my constructor it doesn't show up in the TabControl. The application starts up blank (like the first picture).
As stated above when the application is already running and I click the "Add Image" button it gets added just fine.
I found a property in the TabControl class called Created which states:
"Gets a value indicating whether the control has been created"
So to try and figure out what's going on I write the value of Created to the console just before I call addImage in the constructor. (I have a custom console for debugging my Form applications.)
public ImageViewerApp()
{
InitializeComponent();
TestConsole.WriteLine(imagesTabControl.Created);
addImage(#"D:\Development\Work\Other\Stardock\Start8\_downloaded\Calculator-3-icon.png");
}
The value of Created just before the call to addImage in the constructor is:
False
I put another console output inside the addImage method:
private void doAddImage()
{
TestConsole.WriteLine(imagesTabControl.Created);
OpenFileDialog openFileDialog = new OpenFileDialog();
...
...
}
The value of Created after the app has started and the user presses the "Add Image" button is:
True
Why is it that the TabControl is not Created inside my constructor (even after the InitializeComponent() call) and the once the application is running it is Created?
=UPDATE========================================================================
Based on the suggestion by Hans Passant I have added the following code to my addImage method:
int selectedTabIndex = -1;
if (imagesTabControl.TabCount > 0)
{
selectedTabIndex = imagesTabControl.SelectedIndex;
}
else
{
selectedTabIndex = imagesTabControl.SelectedIndex + 1;
}
imagesTabControl.TabPages.Insert(selectedTabIndex, tabPage);
imagesTabControl.SelectedIndex = selectedTabIndex;
This doesn't work.
===============================================================================
=UPDATE2=======================================================================
int selectedTabIndex = imagesTabControl.SelectedIndex;
if (imagesTabControl.TabCount == 0) selectedTabIndex = -1;
imagesTabControl.TabPages.Insert(selectedTabIndex, tabPage);
imagesTabControl.SelectedIndex = selectedTabIndex;
This causes the following Exception:
{"InvalidArgument=Value of '-1' is not valid for 'index'.\r\nParameter name: index"}
===============================================================================
=UPDATE3=======================================================================
I tried the folllowing code:
int selectedTabIndex = imagesTabControl.SelectedIndex;
if (imagesTabControl.TabCount == 0) selectedTabIndex = -1;
imagesTabControl.TabPages.Insert(selectedTabIndex + 1, tabPage);
imagesTabControl.SelectedIndex = selectedTabIndex + 1;
This one doesn't throw an exception but again no tab page added after calling
addImage in the constructor.
===============================================================================
=UPDATE4=======================================================================
I have kindof given up on adding an image in the constructor. So instead I am using an enum RunMode and a variable RUN_MODE of that type. Then, if RUN_MODE == RunMode.TESTI call a method to add a random image when I click the button. (The OpenFileDialog is not used. I just parse through all the image files in the fixed directory IMAGE_DIRECTORY.
enum RunMode { NORMAL, TEST }
private static string IMAGE_DIRECTORY = #"D:\\Work\Images";
...
...
private void doAddImage()
{
if (RUN_MODE == RunMode.TEST)
{
addRandomImage();
return;
}
OpenFileDialog openFileDialog = new OpenFileDialog();
openFileDialog.Filter = Constants.Global.IMAGE_FILE_FILTER();
if (openFileDialog.ShowDialog() == System.Windows.Forms.DialogResult.OK)
{
string imageFileName = openFileDialog.FileName;
addImage(imageFileName);
}
}
private void addRandomImage()
{
string[] allFiles = Directory.GetFiles(IMAGE_DIRECTORY);
List<string> imageFileNames = new List<string>();
foreach (string file in allFiles)
{
bool isImageFile = Constants.Global.IMAGE_EXTENSIONS.Contains(Path.GetExtension(file));
if (isImageFile)
{
imageFileNames.Add(file);
}
}
int randomIndex = new Random().Next(imageFileNames.Count);
addImage(imageFileNames.ElementAt(randomIndex));
}
This works. Now when I click the "Add Image" button during TEST_MODE I skip the
OpenFileDialog and just add a random image.
I would like to understand the issues with TabControl but at this point I just
need to continue development. My current solution works great.
As I person who like to understand everything I would like to use other people's
suggestions so I will keep monitoring this question for a solution.
===============================================================================
JonP's answer gave me the idea to just wait for the window handle to be created before inserting the tab, so I tried some events occuring between Form construction and Tab Control display.
I found it to work with both the Load or Shown events:
Right-click on the Form (the root, not child controls) in the Designer view > Properties > Events (flash icon) > Behavior > enter a method name for the Load or Shown event and confirm. To generate a Load event callback you can also double-click on the Form itself. This should generate something like this:
this.Load += new System.EventHandler(this.Form1_Load);
// or
this.Shown += new System.EventHandler(this.Form1_Shown);
Setup the tabs in the callback:
private void Form1_Load(object sender, EventArgs e)
{
// Add image (this will call imagesTabControl.TabPages.Insert(selectedTabIndex + 1, tabPage))
// This must be done on Load event because Insert requires
// the window handle, which is not ready in the constructor
addImage(#"path_to_image.png");
}
I have had this problem too and have found a workaround; I think it must be a bug with Insert():
Don't use Insert(), it usually does nothing, use Add() instead; this reliably adds a TabPage to the end of the collection.
After adding it swap it with the tab position where you actually want it.
imagesTabControl.TabPages.Add(tabPage);
// Now swap the two tabs:
imagesTabControl.TabPages[imagesTabControl.TabCount - 1] = imagesTabControl.TabPages[selectedTabIndex + 1];
imagesTabControl.TabPage[selectedTabIndex + 1] = tabPage;
Your mileage may vary of course :-)
Stop Press! An even better fix is to read the class's Handle member before calling Insert():
var handle = imagesTabControl.Handle;
Insert() works perfectly after you do that. Obvious isn't it???? The help page for Handle has this possible relevant Remark showing that the object actually does something when you read Handle:
The value of the Handle property is a Windows HWND. If the handle has not yet been created, referencing this property will force the handle to be created.
You could remove the TabControl from the designer and then instead just manually create the TabControl programmatically and add it to the Form immediately after InitializeComponent(). Then after you create the TabControl, call addImage(). Something like:
InitializeComponent();
TabControl tc = new TabControl();
tc.Location = new Point(10, 10);
tc.Size = new Size(100, 100);
tc.Visible = true;
tc.Anchor = (AnchorStyles.Bottom | AnchorStyles.Right | AnchorStyles.Left | AnchorStyles.Top);
this.Controls.Add(tc)
addImage("c:\pathToImage\image.bmp");
For my C# Windows Form Application, I have created a flowlayoutpanel that contains several panels. Inside the panel, I have a button "Clear" for each and every single panel.
How do I write the event handler for the code for the button "Clear" such that once I have click the button, the panel would sort of be "Removed" from the flowlayoutpanel.
This is a short part of the code of the adding of panels to the flowlayoutpanel.
nFlowPanel.Controls.Add(createNotificationPanel());
nFlowPanel.Controls.Add(createNotificationPanel());
nFlowPanel.Controls.Add(createNotificationPanel());
nFlowPanel.Controls.Add(createNotificationPanelImpt());
nFlowPanel.Controls.Add(createNotificationPanelImpt());
and this is the code for the button "Clear"
Button btnClear = new Button
{
Text = "Clear",
Name = "btnClear",
Location = new Point(416, 17)
};
p.Controls.Add(btnClear);
btnClear.Click += new EventHandler(buttonClear_Click);
So what should i write in the following method to have the effect of removing e.g. the second panel that was added in the first part of code I have written?
void buttonClear_Click(object sender, EventArgs e)
{
throw new NotImplementedException();
}
EDIT
the code for creating my panel is
var p = new Panel
{
BorderStyle = BorderStyle.FixedSingle ,
Size = new Size(506,100),
Name = "notifyPanel"
};
and the code for creating my FlowLayoutPanel is
var nFlowPanel = new FlowLayoutPanel
{
FlowDirection = FlowDirection.TopDown,
WrapContents = false,
AutoScroll = true,
Size = new Size(530, 377),
Location = new Point(13, 145)
};
and the code for my button clear is
void buttonClear_Click(object sender, EventArgs e)
{
var button = (Control)sender;
var panel = button.Parent.Controls["notifyPanel"];
panel.Dispose();
}
however it gives the error
Object reference not set to an instance of an object.
on the panel.Dispose() line.
anyone can help?
The Controls.Remove() method is very dangerous, it doesn't dispose the control. Which will live on, moved to the so-called parking window, using up both Windows and managed resources. After a bit less than 10,000 times doing this it crashes your program when Windows is no longer willing to let you create any more windows.
Call the control's Dispose() method instead. That also automatically removes the control from its container.
void buttonClear_Click(object sender, EventArgs e)
{
var panel = nFlowPanel.Controls["notifyPanel"];
panel.Dispose();
}
You can do it like this:
nFlowPanel.Controls.Remove((sender as Button).Parent);
I will suggest you to use List for this. Before adding Panels in the FlowLayoutpanel, add them in the List. Then just remove the indexed panel from the flowlayoutpanel.
Panel pnlTemp = (panel)list[index];
nFlowPanel.Controls.Remove(pnlTemp);
To get the index of the button you have to add your buttons also to your list and after clicking any button, search the button in the list and get the index of the button where it is saved in the list. If my code is unclear, let me know. but I feel your task is that complex. I am not sure but this link may be of some help.
Hope it helps.
I'm trying to extend TextBox to add a Label to the left of it and treat it as one Control so I don't have to keep track of both of their sizes, locations, etc.
I've created a TextBoxWithLabel class that extends Control and has TextBox and Label fields, but I'm not really sure what to do for onPaint() - do I have to tell it to manually draw both items? If so, how? I'm guessing the default inherited behaviour doesn't go so far as 'check if I contain any child Controls and if I do, draw them'...
Is this even the best way to do it? I previously had my class extend TextBox and just added the Label field, but of course that didn't get added to the Panel containing the TextBoxWithLabel and so wasn't drawn.
Any suggestions or pokes in the right direction appreciated.
Thanks,
Alex
The typical approach here is a UserControl in which you put both the label and the text box. It is painful though, you have to add a lot of the properties and events of the text box to the user control so it at least resembles a text box. Ugly boilerplate code.
Another way to do it is to make a custom text box that sneaks in a label control on the parent. That completely behaves like a TextBox without having to do any work. Add a new class to your project and paste the code shown below. Compile. Drop the new control from the top of the toolbox onto your form. Set the Description property to the text you want to see appear in the label.
using System;
using System.Drawing;
using System.Windows.Forms;
class MyTextBox : TextBox {
private Label label;
public MyTextBox() {
label = new Label();
label.AutoSize = true;
label.Font = this.Font;
label.Location = this.Location;
label.Resize += new EventHandler(label_Resize);
}
protected override void OnParentChanged(EventArgs e) {
// Keeps label on the same parent as the text box
base.OnParentChanged(e);
label.Parent = this.Parent; // NOTE: no dispose necessary
}
private void moveLabel() {
// Keep label right-aligned to the left of the text box
label.Location = new Point(this.Left - label.Width - 10, this.Top);
}
private void label_Resize(object sender, EventArgs e) {
moveLabel();
}
protected override void OnLocationChanged(EventArgs e) {
base.OnLocationChanged(e);
moveLabel();
}
public string Description {
get { return label.Text; }
set { label.Text = value; }
}
public override Font Font {
get { return base.Font; }
set { base.Font = label.Font = value; }
}
}
Did you consider using a UserControl? The benefit of a usercontrol is that you can easily put your label and textbox with correct relative positioning.
Custom Control - An extension to an existing control
User Control - A composition of multiple existing controls
Choose your candidate.