在TabControl中选择标签页而不会窃取焦点

Question

Using TabControl.SelectTab("...") shows the tab but it also gives the tab focus. I would like to show a particular tab, but keep focus where it is.

I have data rows in a grid. Based on properties of the selected row, I show a different tab page to have a different UI layout. But when using arrow keys to scroll through rows, the focus switches to the selected tab -- which I don't want to happen.

Thanks.

Answer 1

You can try disabling the TabControl before setting the selected tab, then re-enabling it. This will prevent it from taking focus. I tested this on a tab control with a few controls on it, and didn't see any visual change, but you'll have to try it in your UI and see whether it's ok for you.

tabControl1.Enabled = false;
tabControl1.SelectTab("tabPage4");
tabControl1.Enabled = true;

To be safe, you could put the line to re-enable the TabControl in a finally block to make sure it doesn't get left disabled.

Answer 2

I don't think there's a built-in function, but you can do in this way:

private bool skipSelectionChanged = false;

private void dataGridView_SelectionChanged(object sender, EventArgs e)
{
    if (skipSelectionChanged)
        return;

    // supposing we decide tab[0] has to be selected...
    this.SelectTabWithoutFocus(this.tabControl1.TabPages[0]);
}

private void SelectTabWithoutFocus(TabPage tabPage)
{
    this.skipSelectionChanged = true;

    // "this" is the form in my case, so you get the current focused control
    // (ActiveControl), backup it, and re-set it after Tab activation

    var prevFocusedControl = this.ActiveControl;
    if (this.ActiveControl != null)
    {
        this.tabControl1.SelectedTab = tabPage;
        prevFocusedControl.Focus();
    }
    this.skipSelectionChanged = false;
}

Here, I backup the current focused control, select the desired tab, and finally set the focus to the original control.

Skipping boolean is necessary, because giving the focus to the grid you trigger SelectionChanged event again, causing infinite looping.

Answer 3

This selects the tab pages while keeping the focus on top, as asked here above:

            tc.TabPages[0].Enabled = false;
            tc.SelectTab(0);
            tc.TabPages[0].Enabled = true;

tc is here my instance for the TabControl type (ie it IS my tab control, and it has a few "tab pages"). This works properly for me. My purpose is to loop through these tab pages with the Left and Right keys (arrows) ie when I go forwards (by Key.Right ) and reach the last tabpage I want to have my focus on [0] without activating the DataGridView which I have in that page, and when I go backwards (by Key.Left ) and reach [0] I want to have [tc.TabCount - 1] enabled, which is the last one. The code for this case is:

            tc.TabPages[tc.TabCount - 1].Enabled = false;
            tc.SelectTab(tc.TabCount - 1);
            tc.TabPages[tc.TabCount - 1].Enabled = true;

The complete piece of code is:

    private bool KeyTc(System.Windows.Forms.Keys keyData)
    {
        if (keyData == K.Left && tc.SelectedIndex == 0)
        {
            tc.TabPages[tc.TabCount - 1].Enabled = false;
            tc.SelectTab(tc.TabCount - 1);
            tc.TabPages[tc.TabCount - 1].Enabled = true;
            return true;
        }
        else if (keyData == K.Right && tc.SelectedIndex == tc.TabCount - 1)
        {
            tc.TabPages[0].Enabled = false;
            tc.SelectTab(0);
            tc.TabPages[0].Enabled = true;
            return true;
        }
        return false;
    }

This bool KeyTc is returned to a case in a switch statement for key evaluation in:

protected override bool ProcessCmdKey(ref Message keyMsg, Keys keyData)
    { switch keyData { ... } }

Answer 4

Base on the solution proposed by "Jeff Ogata : You can try disabling the TabControl before setting the selected tab, then re-enabling it. This will prevent it from taking focus", here bellow my solution:

tabMain.SelectedPageChanging += (s, e) =>
        { 
            tabMain.Enabled = false;
        };

        tabMain.SelectedPageChanged += (s, e) =>
        {
            tabMain.Enabled = true;                
        };

Note: this code is using DevExpress "DevExpress.XtraTab.XtraTabControl".