这是一个小技巧，因为SelectedIndex属性值实际上会改变，但如果SelectedIndexChanging事件被取消，它会再次改变，但从用户的Angular 来看，它肯定会工作。如果您正在使用SelectedValue，则可能需要检查它们的行为。

internal class ComboBoxEx : ComboBox
{
    private int previousSelectedIndex = -1;
    private bool isRevertingSelectedIndex = false;

    public event EventHandler<CancelEventArgs> SelectedIndexChanging;

    protected virtual void OnSelectedIndexChanging(CancelEventArgs e)
    {
        SelectedIndexChanging?.Invoke(this, e);
    }

    protected override void OnSelectedIndexChanged(EventArgs e)
    {
        if (isRevertingSelectedIndex)
        {
            isRevertingSelectedIndex = false;

            // Ignore the event altogether.
            return;
        }

        var cea = new CancelEventArgs();

        OnSelectedIndexChanging(cea);

        if (cea.Cancel)
        {
            // Revert the index to its previous value, so it appears not to have changed.
            isRevertingSelectedIndex = true;
            SelectedIndex = previousSelectedIndex;

            // Do not process the event any further.
            return;
        }

        // Commit the index change.
        previousSelectedIndex = SelectedIndex;

        base.OnSelectedIndexChanged(e);
    }
}

您只需处理SelectedIndexChanging事件，并将e.Cancel设置为true（如果SelectedIndex不应更改）。

另一个小黑客...创建一个字段（元组），您可以在其中跟踪最后选择的索引以及它是否可以更改...

(bool blockChanges, int atIndex) comboRestriction = (false, 0);

在SelectionChanged方法中添加以下内容：

ComboBox combo = (ComboBox)sender;

if (comboRestriction.blockChanges && combo.SelectedIndex != comboRestriction.atIndex)
{
     combo.SelectedIndex = comboRestriction.atIndex;
     return;
}
else if (comboRestriction.blockChanges)
{
      return;
 }

// Combo Changed - track last index
comboRestriction = (false, combo.SelectedIndex);
...

当你想“阻止”comboBox时，将其设置为“true”：

comboRestriction.blockChanges = true;