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.
Related
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 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.
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).
I'm not very experienced on c#. I'm working with winforms and I'm looking for a way to create something like a list of elements with this template , something like the autocompletion list of visual studio.
Is it possible to do? Shall I use listbox or listview?
EDIT
Sorry my question wasn't clear I don't want to create an autocomplete but what i want to create is something like this a list of things with an icon next to the text of that thing.
As I understand from your question, you can create custom UserControl or create a Form and put ListBox in it. If you use From be sure that you change border style layout, just set it to none. After creation for use it you should create form and show it where you want like this:
FrmAutoComplete x = new FrmAutoComplete();
x.Show();
you can put this form in ToolTipItem and show it.
Good luck.
THis is a quick and dirty example of using images in your Listview control. Since I don;t have a lot of information about what you plan to do, I tried to keep is simple.
In short, you need to load some images into one of the ImageLists (Large or Small) built into the Listview control and assign them keys so that you can assign them to specific list items as you add them.
The trick to this is determining which image to use for a specific list item (assuming there are different images assigned to different list items depending on some differentiating factor. For this example, I used an arbitrary assignment of "cars" or "trucks," and simply decided that the first five items in the list would be cars, and the last five would be trucks. I then assigned each image appropriately, using the image key as I added each listview item. You can do this for more complex scenarios, and when using the image key, it does not matter what order the items are added.
For this use case, you will want to create or use images with dimensions of 16 x 16 pixels. I went ahead and added two images to my project resource file, then simply accessed them using the project Properties.Resources name space. There are other ways to do this as well, but this is the most convenient for me.
Hope that helps.
public partial class Form1 : Form
{
static string CAR_IMAGE_KEY = "Car";
static string TRUCK_IMAGE_KEY = "Truck";
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
this.SetupListview();
this.LoadListView();
}
private void SetupListview()
{
var imgList = new ImageList();
imgList.Images.Add("Car", Properties.Resources.jpgCarImage);
imgList.Images.Add("Truck", Properties.Resources.jpgTruckImage);
var lv = this.listView1;
lv.View = View.List;
lv.SmallImageList = imgList;
}
private void LoadListView()
{
for(int i = 1; i <= 10; i++)
{
string currentImageKey = CAR_IMAGE_KEY;
if(i > 5) currentImageKey = TRUCK_IMAGE_KEY;
var item = this.listView1.Items.Add("Item" + i.ToString(), currentImageKey);
}
}
I've created a custom user control with a grid. I'd like to bind this grid once, and use it over and over again in my app. If I put the binding within the control, the data is retrieved as many times as I use the control. How do I bind it only once??
public ClientLookUp()
{
InitializeComponent();
vw_clientsTableAdapter.Fill(dsclientlkup.vw_clients); //This occurs as many times as I have the user control, instead of just once.
}
Well anything you put in the constructor will be executed every time you construct the object!
What about providing an Initialize method that you can call whenever you need to reload the data??
If you want to load the data only once, then load it either into a static variable or a separate class that is referenced by the control.
If you really want to use the same single grid in your control over and over, you could create a single, static grid, and have your ClientLookUp constructor add it to the right place—Panel, or whatever—whenever a new one is created.
Before you go do this road however, ask yourself if this is really what you want to do. Having the same identical grid existing in many places may cause you problems down the road. If you want to support in-grid editing, you'll find that changing one value changes the identical value in all your other grids..
EDIT
I tried getting the below code to work, but I'm not sure this approach will be possible. It seems as though the minute you try to attach the same UI element into more than one place, it gets moved out of the last place you put it; it doesn't look like you can have the same grid being in more than one place at once. This makes sense when you think about it.
Here's the code I tried. Maybe it will be of some use to you.
public UserControl1()
{
InitializeComponent();
this.Controls.Add(myStaticGridView);
myStaticGridView.Dock = DockStyle.Fill;
}
static DataGridView _staticGrid;
public DataGridView myStaticGridView
{
get
{
if (_staticGrid != null)
return _staticGrid;
_staticGrid = new DataGridView();
_staticGrid.Columns.Add("A", "A");
_staticGrid.Columns.Add("B", "B");
_staticGrid.Columns.Add("C", "C");
_staticGrid.Columns[0].DataPropertyName = "A";
_staticGrid.Columns[1].DataPropertyName = "B";
_staticGrid.Columns[2].DataPropertyName = "C";
_staticGrid.DataSource = new[] {
new { A = "someA", B = "someB", C = "someC"},
new { A = "someA", B = "someB", C = "someC"},
new { A = "someA", B = "someB", C = "someC"},
new { A = "someA", B = "someB", C = "someC"},
};
return _staticGrid;
}
}
And then loading the control like this:
private void button1_Click(object sender, EventArgs e)
{
flowLayoutPanel1.Controls.Add(new UserControl1());
}