WinForms AcceptButton not working?

Question

Ok, this is bugging me, and I just can't figure out what is wrong...

I have made two forms. First form just has a simple button on it, which opens the other as a dialog like so:

using (Form2 f = new Form2())
{
    if (f.ShowDialog() != DialogResult.OK)
        MessageBox.Show("Not OK");
    else
        MessageBox.Show("OK");
}

The second, which is that Form2, has two buttons on it. All I have done is to set the forms AcceptButton to one, and CancelButton to the other. In my head this is all that should be needed to make this work. But when I run it, I click on the button which opens up Form2. I can now click on the one set as CancelButton, and I get the "Not OK" message box. But when I click on the one set as AcceptButton, nothing happens? The InitializeComponent code of Form2 looks like this:

private void InitializeComponent()
{
    this.button1 = new System.Windows.Forms.Button();
    this.button2 = new System.Windows.Forms.Button();
    this.SuspendLayout();
    // 
    // button1
    // 
    this.button1.Location = new System.Drawing.Point(211, 13);
    this.button1.Name = "button1";
    this.button1.Size = new System.Drawing.Size(75, 23);
    this.button1.TabIndex = 0;
    this.button1.Text = "button1";
    this.button1.UseVisualStyleBackColor = true;
    // 
    // button2
    // 
    this.button2.DialogResult = System.Windows.Forms.DialogResult.Cancel;
    this.button2.Location = new System.Drawing.Point(130, 13);
    this.button2.Name = "button2";
    this.button2.Size = new System.Drawing.Size(75, 23);
    this.button2.TabIndex = 1;
    this.button2.Text = "button2";
    this.button2.UseVisualStyleBackColor = true;
    // 
    // Form2
    // 
    this.AcceptButton = this.button1;
    this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
    this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
    this.CancelButton = this.button2;
    this.ClientSize = new System.Drawing.Size(298, 59);
    this.Controls.Add(this.button2);
    this.Controls.Add(this.button1);
    this.Name = "Form2";
    this.Text = "Form2";
    this.Load += new System.EventHandler(this.Form2_Load);
    this.ResumeLayout(false);
}

I have done nothing else than add those two buttons, and set the AcceptButton and CancelButton. Why doesn't it work?

Answer 1

Just setting the AcceptButton/CancelButton is not enough. This just tells which button should be invoked on Enter/Esc. You have to set the DialogResult in the Button handler.

Answer 2

Try setting DialogResult on button1

this.button1.DialogResult = System.Windows.Forms.DialogResult.OK;

Answer 3

Definitely try the tutorial How to easily apply AcceptButton and CancelButton for custom dialog box in Winform.

Answer 4

I had an issue with the AcceptButton not working and while the DialogResult suggestion was part of the fix, I had 2 other things that needed to change:

1. My button was not visible - Intentionally because I wanted to stop the "ding" when a carriage return was "pressed" by scanning a barcode.
2. The container that the button was inside made a difference. I had to have it in the same container, in my case a Forms.Panel, as the textbox that was trying to access it. I'm not sure why this would make a difference, but it did.

I hope this helps someone.

Answer 5

You need to set the KeyPreview property of the form to True, the default value is False. Remember that if focus is set to any other button rather than the AcceptButton the Enter key will execute this button