Clicking on a listbox means I can't click on anything else on the form.

Question

I'm using a databound listbox in a C# WinForm application.

When I click on an item in the listbox nothing else on the form works, even when I click on the close button the form doesn't close. Everything works fine until I select an item.

What I have tried to do is in the listbox1_SelectedIndexChanged set the listbox1 focus to false but that didn't work.

Code sample: This is the code that assigns the listbox to the data source:

this.ListBox1.DataBindings.Add(new System.Windows.Forms.Binding("SelectedValue", this.table1BindingSource, "PrimaryKeyId", true));
this.ListBox1.DataSource = this.table1BindingSource;
this.ListBox1.DisplayMember = "Name";
this.ListBox1.Font = new System.Drawing.Font("Microsoft Sans Serif", 14.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
this.ListBox1.FormattingEnabled = true;
this.ListBox1.ItemHeight = 24;
this.ListBox1.Location = new System.Drawing.Point(185, 28);
this.ListBox1.Name = "ListBox1";
this.ListBox1.Size = new System.Drawing.Size(660, 532);
this.ListBox1.TabIndex = 7;
this.ListBox1.ValueMember = "Name";
this.ListBox1.SelectedIndexChanged += new System.EventHandler(this.ListBox1_SelectedIndexChanged);

ListBox1 isn't referenced anywhere else. This is the initial code I was using before:

private void ListBox1_SelectedIndexChanged(object sender, EventArgs e)
{
    ListBox1.Focus().Equals(false);
}

This is the code I am now running:

private void ListBox1_SelectedIndexChanged(object sender, EventArgs e)
{
    GroupBox1.Focus().Equals(true);
}

Then on Windows load I have: table1TableAdapter.Fill(this.Application1DataSet.Table1); I've debug the windows load and the listbox1 method so I don't think it's a loop. Also the app doesn't crash so I don't think it's a loop.

Answer 1

What did work was setting the focus to another control on the form. But it's still a weird problem.

Answer 2

It will work if you write:

listBox1.ValueMember = "PrimaryKeyId";

Answer 3

This code:

ListBox1.Focus().Equals(false);

...does not "un-focus" the list box.

If you look at the documentation for Focus, you'll see that it focuses the control, if it can, otherwise it returns false.

Tacking on .Equals(false) simply compares the result of that call to the value false. In other words, it's equivalent to writing this:

!ListBox1.Focus()

Which pretty obviously does not remove focus from the list box, it actually sets focus to the list box in most cases. You are simply making a comparison on the return value and then throwing the result of the comparison away.

As you discovered yourself, there is no method to remove focus from a control. You can only set focus to some other control.

Answer 4

I have also encountered this when developing an application but thank God, this worked.

private void listBox1_SelectedIndexChanged(object sender, EventArgs e) {

        listBox1.SelectedIndex = -1;


    }