How do I resize a custom control I've built

Question

I'm resizing my custom control using the following code:

private void Form1_Resize_1(object sender, EventArgs e)
{

    textBox1.Text = this.Width.ToString();
    textBox2.Text = (this.Height - 200).ToString();

   canvas21.Size = new System.Drawing.Size(this.ClientSize.Width,  this.ClientSize.Height - this.Top - 15);

    canvas21.Invalidate();

}

I just want the top left corner of the custom control(0, 105) to stay in place, and the control to resize along with the form, but for some reason this does not work. When I resize the control stays in place, but automatically resizes to fill out the rest of the form.

Is there any way to get a list of everything that affects the size of a usercontrol. In order to search for other places the size i set, which i might have overlooked?

Answer 1

If you want your control to always resize with the form, you can use the Anchor property to set it to be anchored to one or more sides of the form so that you don't have to have your own resizing code (assuming that the standard resizing functionality you get with this fits your needs).

You have to make sure that the Dock property isn't set though, otherwise it might fill the whole form (or one side of the form depending on the setting).

Answer 2

There's really no reason why setting the height and then anchoring to every side (with docking set to none) shouldn't work.

However, I did notice an error in the logic of your provided code. You have:

canvas21.Size = new System.Drawing.Size(this.ClientSize.Width,  this.ClientSize.Height - this.Top - 15);

When it should actually be:

canvas21.Size = new System.Drawing.Size(this.ClientSize.Width,  this.ClientSize.Height - this.canvas21.Top - 15);

You were just taking the top of the form, rather than the top of canvas21, which is what you need.

That seems to do exactly what you want, at least from my standpoint. If it doesn't quite work, is it simply not resizing at all for you or is it resizing to the wrong size?

Answer 3

Using the Anchor property is the better way to go if you can set it. The ones to lock are

left, top, right, bottom (all!)

Anchor keeps you control x units form the side that you have locked, so that it is always the same distance from the sides.

If that is not an option, or just to get your code going, try this

private void Form1_Resize_1(object sender, EventArgs e)
{
    textBox1.Text = this.Width.ToString();
    textBox2.Text = (this.Height - 200).ToString();

    int iTop = canvas21.Top;
    int iLeft = canvas21.Left;
    // - 200 - iTop keeps it 200 from the bottom, -iLeft keeps i stuck to right
    canvas21.Size = new System.Drawing.Size(this.Width -iLeft, this.Height-200 -iTop);
    canvas21.Left = iLeft;   // move back
    canvas21.Top = iTop;   // move back
    canvas21.Invalidate();
}

To keep it 15 pixels in the bottom, change 200 above to 15. Or, set it at 15 at design time or via code, the activate the bottom anchor.

Answer 4

For controls other than your custom control can you get it to resize properly? For example if you put in a richtextbox and set Anchor accordingly (All) will it resize properly for you? If it does then there must be somthing fishy with the sizing of your control, BUT you could maybe cheat it by doing this...

1. Create a Panel that is the exact size and Anchoring you would like from your control.
2. Add your control to the Panel and set Dock to "Fill". Effectively you will fill the panel with your control and use the panel to control resizing on the form.

If of course your panel doesn't resize properly either then this won't work for you. Granted this is likely a workaround to an underlying code issue that in a perfect world would be remidied on the control itself.

Answer 5

I'm looking at resizing a user control, and I'm using many different events to handle this (eg. OnSizeChanged, OnFontChanged, OnTextChanged)

Depending on how your text Boxes fit in your control will make a difference, but if your primary container has the property AutoScaleMode or AutoSize then you may find you are not catching all the relevant events.

I appologise in advance if I'm off-beam as I'm new to this sort of thing.

ps. I didn't find your post initially as I'd been looking at tags Windows-forms-designer and custom-control. I really don't know which tags I should use and can't use all the possibilities as the limit of 5 takes over!

Answer 6

Dude, you're going to kick yourself. You don't want ClientSize.Height - Top - 15, you want ClientSize.Height - canvas21.Top - 15. That's it!

private void Form1_Resize_1(object sender, EventArgs e)
{
    textBox1.Text = this.Width.ToString();
    textBox2.Text = (this.Height - 200).ToString();

    canvas21.Size = new System.Drawing.Size(this.ClientSize.Width,  
        this.ClientSize.Height - canvas21.Top - 15);

    canvas21.Invalidate();
}