I'm fairly new to C# (and programming in general) so stick with me if I make any huge errors or talk complete bull.
So what I'm trying to do is have a private void that resizes the background image of a button. I send the name of the button to the private void via a string. Anyway, the code looks something like this:
ButtonResize("Zwaard");
protected void ButtonResize(string Button)
{
string ButNaam = "btn" + Button;
Button Butnaam = new Button();
Butnaam.Text = ButNaam;
if (Butnaam.BackgroundImage == null)
{
return;
}
else
{
var bm = new Bitmap(Butnaam.BackgroundImage, new Size(Butnaam.Width, Butnaam.Height));
Butnaam.BackgroundImage = bm;
}
}
But it doesn't work like that. I can't seem to find a way to declare a new object named the value I have in a string. What I want my code to do is instead of making a button called "Butnaam", I want it to create a button called btnZwaard (the value of the string Butnaam).
How do I tell C# I want the value of the variable to be the name of a new button, not literally what I type?
Thanks in advance.
Are you looking for something like this? By passing the Button to the method you can then act on the object. If this is what you are looking for then you should read Passing Reference-Type Parameters
protected void ButtonResize(Button button)
{
if (button != null && button.BackgroundImage != null)
{
button.BackgroundImage = new Bitmap(button.BackgroundImage, new Size(newWidth, newHeight));
}
}
A string is a piece of text. You subsequently refer to it as a class, which is wrong. Assuming it were right you create a new button rather than "resize its image".
What you want to do to get you started is create a new function in the same class as the dialog that has the button. That function can resize the image of the control.
Edit: this doesn't seem like a good starting point for learning a language, btw. Please find a good online tutorial for starting in C# (e.g. a hello world application).
Related
I've been working on making a project of mine more modular. Something I've wanted to do is have multiple buttons use the same function when they perform a similar action, but with different values. I've been stuck on trying to apply this to the following situation:
"When this button is clicked, have the user select an image, and then have a PictureBox display the selected image". Each button has its own PictureBox. All Controls have been created before runtime.
Hope that makes sense!
My last attempt can be seen in the code below- I have tried assigning the Controls(Button and PictureBox) to variables to be stored together in a class. There's 6 of these classes all included within a single List.
I've also tried to store only the Control Names and then using this.Controls.Find to retrieve the Controls.
I've tried quite a few smaller changes such as passing by reference, making the List static, and things such as that would (somehow)magically do the trick- I've gotten desperate.
public class score_control
{
public Button score_button;
public PictureBox score_picture;
public int picture_index;
}
public List<string> score_boxes_names = new List<string>();
public List<score_control> score_boxes = new List<score_control>();
public void add_score_control(Button button, PictureBox pictureBox)
{
score_control new_score = new score_control();
new_score.score_button = button;
new_score.score_picture = pictureBox;
new_score.picture_index = score_boxes.Count();
score_boxes.Add(new_score);
score_boxes_names.Add(button.Name);
}
public score_control find_score_control(string name)
{
int index = score_boxes_names.IndexOf(name);
return score_boxes[index];
}
public frm_settings()
{
InitializeComponent();
add_score_control(btn_score1_image1, pic_score1_image1);
add_score_control(btn_score1_image2, pic_score1_image2);
add_score_control(btn_score1_image3, pic_score1_image3);
add_score_control(btn_score2_image1, pic_score2_image1);
add_score_control(btn_score2_image2, pic_score2_image2);
add_score_control(btn_score2_image3, pic_score2_image3);
}
private void score_button_Click(object sender, EventArgs e)
{
Button image_button = (Button)sender;
if (ofd_png.ShowDialog() == DialogResult.OK)
{
score_control clicked_control = find_score_control(image_button.Name);
score_image[clicked_control.picture_index] = ofd_png.FileName;
clicked_control.score_picture.Image = Image.FromFile(ofd_png.FileName);
}
}
The problem seems centered around this line:
clicked_control.score_picture.Image = Image.FromFile(ofd_png.FileName);
The program throws a NullReferenceException , but clickedcontrol is being recognized in the Local Watch, as well as score_image being noted to be a PictureBox(as it should be).
When I instead held the Control Names in the class, I had broke this line down into multiple lines, but the following line produced a NullReferenceException:
Control[] find_control = this.Controls.Find(clicked_control.score_picture, true);
In this case, clicked_control.score_picture would be a string containing the PictureBox Name. Again, the Local Watch showed that it clicked_control was not null, and neither was score_picture.
Any help figuring out how to properly store a Control within a variable to later be used to modify that Control's properties would be greatly appreciated.
dontpanic was able to help me out with this one. The issue was actually outside of this code - it had to do with the line score_image[clicked_control.picture_index] = ofd_png.FileName;. The way score_image was initialized as an array was incorrect. Fixing that made everything work fine.
This is probably a basic question, but I can't find answers because the terms are generic.
I am building a WinForm aplication. Its purpose is to set up memory in a certain chip. I think the best way to organize the application is to have a user control for each chip type, derived from a generic parent class. Think of the children as "iphone," "android" and "blackberry," derived from a parent class "phone".
VS2017 Designer has a Panel where I want the control to be. On startup, I generate an object of the base class and add it to the panel. When I press a button, the old object is deleted and replaced with a new one. Each class has just one control, a label with distinctive text.
The problem is, after I press the button, I see both texts. The panel's Controls collection has just one element, but I see the text from both objects. I have tried Refresh, Update and Invalidate withe the same results.
What do I have to do to make the old text "go away" so the only thing I see is the latest object?
private ChipMemBase ChipMemControl = new ChipMemBase();
public Form1()
{
InitializeComponent();
//tbFeedback.Text = string.Format(fmtString, 0, 1, 2, 3, 4, 5);
cbChipName.SelectedIndex = 0;
tbVersion.Text = Version;
OriginalWindowColor = tbFeedback.BackColor;
ShowChipMemControl();
PrintToFeedback(Version);
}
private void ShowChipMemControl()
{
var ctl = pnlChipMem.GetChildAtPoint(new Point(5,5));
if (null != ctl)
{
if (ctl != ChipMemControl)
{
pnlChipMem.Controls.Remove(ctl);
ctl.Dispose();
pnlChipMem.Update();
Refresh();
}
}
if (null != ChipMemControl)
{
pnlChipMem.Controls.Add(ChipMemControl);
}
}
private void btnMakeChipMemory_Click(object sender, EventArgs e)
{
ChipMemControl = new ChipMemGen2();
ShowChipMemControl();
}
Screenshots before and after clicking Create
Your ShowChipMemControl gets the control at point 5,5 and checks if it's a ChipMemControl then removes it.
I'm guessing that the reason it's not getting removed is that the control at point 5,5 is not a ChipMemControl.
You can use:
pnlChipMem.Controls.Clear()
to remove all the controls
Or:
ChipMemControl cmc = pnlChipMem.Controls.OfType<ChipMemBase>().FirstOrDefault();
if (cmc != null)
{
pnlChipMem.Controls.Remove(cmc);
cmc.Dispose();
}
To only remove the first instance of ChipMemBase on your pnlChipMem panel.
Got it. The problem was from inheritance, not window behavior. Control lblDefault in the base class, carrying the inconvenient text, was still present in the child class. I had to make it Public in the base class and remove it in the child class constructor:
InitializeComponent();
Controls.Remove(lblDefault);
lblDefault.Dispose();
lblDefault = null;
The clue was this article and project:
dynamically-and-remove-a-user-control
I'm a newbie in c# and probably going to ask a very easy question, but I've not been able to find anything on the web to help.
I have a tabControl with a TabPage which is containing a TextBox object; this object, when the event "Text changed" is invoked, will perform the change of the parent tabPage's name.
The textbox where I typed "text changed by me" has a method which is managing changing the name of the tabPage:
private void textBox1_TextChanged(object sender, EventArgs e)
{
if (this.textBox1.Text != "")
this.tabControl2.SelectedTab.Text = this.textBox1.Text;
else
this.tabControl2.SelectedTab.Text = "(no name)";
}
Into the current page menu is contained a control to add a new page, which runs this method when the user click on it:
private void addNewPageToolStripMenuItem_Click(object sender, EventArgs e)
{
int numPagine;
string strPagine;
numPagine = this.tabControl2.TabCount;
strPagine = numPagine.ToString();
this.tabControl2.TabPages.Add("new page" + strPagine);
}
...and here is the output, which is expected since I'm just asking to add a new empty tabPage:
So, my question is: how can I make possible that when the user is clicking on "Add new page", rather than creating an empty new tabPage the program is rather creating a page like the first one (i.e. containing a textbox into the same position which has a method to change the text of the parent tabPage that I have just created?
Here is an example.
//..
// create the new page
TabPage tpNew = new TabPage("new page..");
// add it to the tab
this.tabControl2.TabPages.Add(tpNew);
// create one labe with text and location like label1
Label lbl = new Label();
lbl.Text = label1.Text;
lbl.Location = label1.Location;
// create a new textbox..
TextBox tbx = new TextBox();
tbx.Location = textBox1.Location;
tpNew.Controls.Add(lbl);
tpNew.Controls.Add(tbx);
// add code to the new textbox via lambda code:
tbx.TextChanged += ( (sender2, evArgs) =>
{
if (tbx.Text != "")
this.tabControl2.SelectedTab.Text = tbx.Text;
else
this.tabControl2.SelectedTab.Text = "(no name)";
} );
For more complicated layout you may want to consider creating a user control..
You also may want to create the first page with this code; the, of course with real values for text and positions!
For creating a UserControl you go to the project tag and right click Add-UserControl-UserControl and name it, maybe myTagPageUC. Then you can do layout on it like on a form. A rather good example is right here on MSDN
The problem is that is has no connection to the form, meaning you'll have to code all sorts of references to make it work..
I'm not really sure if you may not be better off writing a complete clonePage method instead. It could work like the code above, but would loop over the Controls of the template page and check on the various types to add the right controls..
It really depends on what is more complicated: the Layout or the ties between the pages and the form and its other controls..
I've found similar answers to my question before, but not quite to what I'm trying to do...
In Visual Basic (last I used it, in 06/07) there was an "Index" property you could assign to multiple controls with the same name. I used this primarily to loop through controls, i.e.:
For i = 1 to 500
picSeat(i).Print "Hello"
Next i
Is there a way to do this in C#? I know there is a .IndexOf(), but would that really help for what I'm doing? I want to have multiple controls with the same name, just different index.
This is a Windows Form Application, and I'm using Visual Studio 2012. I am talking about controls, not arrays/lists; this was possible in VB and I was wondering if it was possible at all in C#. So I want to have, say, 30 seats in a theatre. I want to have each seat represented by a picturebox named "picSeat". VB would let me name several objects the exact same, and would assign a value to a control property "Index". That way, I could use the above loop to print "Hello" in every picture box with only 3 lines of code.
No, this feature does not exist in C#, and was never implemented in the transition from classic VB to VB.Net.
What I normally do instead is put each of the controls in question in a common parent container. The Form itself can work, but if you need to distinguish these from others of the same type a GroupBox or Panel control will work, too. Then, you access the controls like this:
foreach (var picBox in parentControl.Controls.OfType<PictureBox>())
{
// do something with each picturebox
}
If you want to use a specific control, just write by name:
pictureBox6.SomeProperty = someValue;
If you need to change a specific control determined at run-time, normally this is in response to a user event:
void PictureBox_Click(object sender, EventArgs e)
{
var picBox = sender As PictureBox;
if (picBox == null) return;
//picBox is now whichever box was clicked
// (assuming you set all your pictureboxes to use this handler)
}
If you really really want the Control Arrays feature, you can do it by adding code to create the array to your form's Load event:
PictureBox[] pictureBoxes = Me.Controls.OfType<PictureBox>().ToArray();
Are we talking WinForms here? I'm not sure, but I don't think you can have multiple controls in winforms with same name. But I vaguely recall doing something similar and the solution was to name them Button_1, Button_2 etc. Then you can iterate through all controls and get your own index.
Beware though that if you want to instanciate a separate control for each seat in a theatre, you might run into some serious performance issues :) I've done something similar to that as well and ended up drawing the whole thing on a canvas and using mouse coordinates to handle the events correctly.
You may want to check out the Uid property of controls.
(http://msdn.microsoft.com/en-us/library/system.windows.uielement.uid(v=vs.110).aspx)
You can access Control through Uid property with the following
private static UIElement FindUid(this DependencyObject parent, string uid)
{
var count = VisualTreeHelper.GetChildrenCount(parent);
if (count == 0) return null;
for (int i = 0; i < count; i++)
{
var el = VisualTreeHelper.GetChild(parent, i) as UIElement;
if (el == null) continue;
if (el.Uid == uid) return el;
el = el.FindUid(uid);
if (el != null) return el;
}
return null;
}
And simply use
var control = FindUid("someUid");
I copied code from this post
If you create an indexed dictionary of your user control, it will behave pretty much the same as in VB6, though you'll not see it on the VS C# GUI. You'll have to get around the placement issues manually. Still - and most importantly -, you'll be able to refer to any instance by the index.
The following example is for 3 pieces for clarity, but of course you could automate every step of the process with appropriate loops.
public partial class Form1 : Form
{
...
Dictionary<int, UserControl1> NameOfUserControlInstance = new Dictionary<int, UserControl1>()
{
{ 1, new UserControl1 {}},
{ 2, new UserControl1 {}},
{ 3, new UserControl1 {}}
};
private void Form1_Load(object sender, EventArgs e)
{
NameOfUserControlInstance[1].Location = new System.Drawing.Point(0, 0);
NameOfUserControlInstance[2].Location = new System.Drawing.Point(200, 0);
NameOfUserControlInstance[3].Location = new System.Drawing.Point(400, 0);
Controls.Add(NameOfUserControlInstance[1]);
Controls.Add(NameOfUserControlInstance[2]);
Controls.Add(NameOfUserControlInstance[3]);
}
...
}
I like using Tags to apply any type of meta data about the controls
for (int i = 0; i< 10; ++i)
{
Button button = new Button();
button.Tag = i;
}
I have fixed my form load problem. I changed it to where the main menu wasn't being called on load event and that fixed the issue. Now my retrieve event gets the version but never passes it to my form.
Here is my code for transferring process:
Where the information is being pulled from:
public string VersionPass { get; set; }
VersionPass = rtxtBoxNewVersion.Text;
This is the main menu where the value will be stored till they click the assign button. This is where it gets the value from the form.
public string VersionNum { get; set; }
VersionEditor newV = new VersionEditor();
newV.ShowDialog();
VersionNum = newV.VersionPass;
newV.Dispose();
Form being transferred to I am using form load because the value will not change: It never get the value into the PassedVersion = passedVersion.VersionNum; field.
MainMenu passedVersion = new MainMenu()
string PassedVersion;
private void Notification_Load(object sender, EventArgs e)
{
PassedVersion = passedVersion.VersionNum;
rTxtBoxVersion.Text = PassedVersion;
}
Having to guess a bit here, but ...
1) Take out new MainMenu() from the Notification_Load call. This is probably stopping the dialog being created properly.
2) If you want to share information you either need to pass it to the new object, for example when you create it:
MyObject = new MyClass(SomeObjectToTellItAbout);
// or maybe like this:
MyObject.InterestingInfo = SomeOtherObject;
If it's truely global information (app version, for example) you could make the info to share static (and then access it like this: MainMenu.MyAppVersion).
Edit based on comments:
You want to get an understanding of classes vs objects. A class is just a design; it's a concept. For example "human". An object is an instantiation of that class/concept/design, for example me. And you (another object). I can't find your name by saying h = new human(); h.name() and nor can you find your version by making a new MainMenu and asking it what version it is! Hope that helps.