Set ComboBox default value without directly changing SelectedIndex

Question

I got a ComboBox with a couple of items. I want to put SelectedIndex of the ComboBox to 0, so when the user starts it, the first item is already selected (as default).

However, doing this (combobox.SelectedIndex = 0;) interferes with my event combobox_SelectedIndexChanged(), which occurs when the user changes the SelectedIndex of the ComboBox, restarting the program:

private void combobox_SelectedIndexChanged(object sender, EventArgs e)
        {
            Process.Start(Application.ExecutablePath);
            this.Close();
        }

This will cause combobox_SelectedIndexChanged() to loop endlessy, ascombobox.SelectedIndex = 0; will trigger it, which again will trigger the other one and so forth...

Is there any way to let the program do something upon changing of the SelectedIndex by the user without this looping?

dovid · Accepted Answer · 2013-12-23T18:17:26.887

7

remove the event handler (by click the lightning bolt at the top of the properties pane. then clear the SelectedIndexChanged handler).

and in constructor code, first set the SelectedValue, and then add the event handler. here:

public Form1()
{
    InitializeComponent();

    comboBox1.SelectedIndex = 0;
    comboBox1.SelectedIndexChanged += combobox_SelectedIndexChanged;
}

private void combobox_SelectedIndexChanged(object sender, EventArgs e)
{
    Process.Start(Application.ExecutablePath);
    this.Close();
}

edited Dec 23 '13 at 18:17

answered Dec 23 '13 at 18:02

dovid

6,354
3
33
73

This oddly triggers an `Sytem.ObjectDisposedExecution`. – jacobz Dec 23 '13 at 18:20
this is another problem. – dovid Dec 23 '13 at 19:20

score 0 · Answer 2 · answered Dec 23 '13 at 18:08

0

You can add a property to suppress event execution

internal bool SupressSelectIndexChanged {get; set;}

private void SomeCallingMethod(){
   this.SupressSelectIndexChanged = true;
   combobox.SelectedIndex = 0;
   this.SupressSelectionIndexChanged = false;
}

private void combobox_SelectIndexChanged(object sender, EventArgs e){
    if(this.SupressSelectIndexChanged){ return; }

    // - execution logic
}

answered Dec 23 '13 at 18:08

Austin

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what SomeCallingMethod()? you can change the property directly. – dovid Dec 23 '13 at 18:44
@lomed SomeCallingMethod() is just an example on how the property can be used. – Austin Dec 23 '13 at 19:18

Set ComboBox default value without directly changing SelectedIndex

2 Answers2