与解决方案1相同，只是我看不出这有什么与组合框有关。我假设您使用的是ToolStripMenu：

Same as solution 1, only I don''t see what this has to do with comboboxes. I assume that you''re using a ToolStripMenu:

private void myToolStripMenuItem_Click(object sender, EventArgs e)
{
    myToolStripMenuItem.BackColor = Color.Red;
}

这是一个代码（ToolStripMenu）：

Here is a code (ToolStripMenu):

private void myToolStripMenuItem_Click(object sender, EventArgs e)
{
    myToolStripMenuItem.BackColor = Color.Red;
    myToolStripMenuItem.BackColor = Color.Green;
    myToolStripMenuItem.BackColor = Color.Blue;
    myToolStripMenuItem.BackColor = Color.Black;
    myToolStripMenuItem.BackColor = Color.White;
    myToolStripMenuItem.BackColor = Color.Gray;
    myToolStripMenuItem.BackColor = Color.Yellow;
    myToolStripMenuItem.BackColor = Color.Magenta;
    //and more

}



你可以双击它（菜单），然后写上.BackColor或.BackgroundColor=Color ._____。



如果你使用另一个菜单，你必须这样做： nameMenu .BackColor = Color。 YourColor

试试这个我的朋友

转到组合框的事件属性（菜单）双击鼠标点击事件

然后使用以下代码。

Try this my friend
Goto event properties of the combobox (Menu) double click on Mouse Click event
then use the following code.

private void comboBox1_MouseClick(object sender, MouseEventArgs e)
        {
            comboBox1.BackColor = Color.Blue;
        }