将项目添加到列表框并选择它

Question

I have a listbox ( SelectionMode is set to MultiExtended as mentioned on this topic ) containing one single entry: "..." . When user double-clicks this a dialog appears to select a single file. When user selects one the dialog disappears and the file should be added to the list. This all works.

My problem is that I want to select only that newly added entry within my listbox . However with the following code both - the "..." and the actual file are selected:

private void lbx_DoubleClick(object sender, EventArgs e)
{
    if (this.lbx.SelectedItem == "..."
            && this.ofdReferences.ShowDialog() == DialogResult.OK
    {
        this.lbx.Items.Insert(this.lbx.SelectedIndex, this.ofdReferences.FileName);
        this.lbx.SetSelected(this.lbx.SelectedIndex - 1, true); // select newly added entry
    }
}

So I also added this line:

this.lbx.SetSelected(this.lbx.SelectedIndex, false);        // unselect ...

Now the "..." -entry is selected instead of the file.

I even tried to use SelectedIndex = this.lbxProjectReferences.SelectedIndex - 1 . This also selects both entries within the list.

Answer 1

The SelectedIndex -property is for single-select-lists. However we can use it on multi-lists also within a double-click-events also because a double-click will implicetly select one single item setting the SelecteItem correctly.

So I used this approach that deletes the list of selected entries and adds only that entry I´m interested in.

this.lbx.Items.Insert(this.lbx.SelectedIndex, this.ofdReferences.FileName);
var idx = this.lbx.SelectedIndex;
this.lbx.SelectedIndices.Clear();
this.lbx.SelectedIndices.Add(idx - 1);