如何在弹出窗口中禁用组合框中的项目

Question

有什么方法可以根据条件禁用组合框中的特定项目。 需要在单击组合框时显示，即弹出显示

Answer 1

步骤 1. 将ComboBox的属性DrawMode设置为OwnerDrawFixed

步骤 2. 使用索引值更改项目颜色

 Font fontValue = new Font("calibri", 12, FontStyle.Regular);

 //Form Load
 private void form_Load(object sender, EventArgs e)
 {
    List<string> lstCombxValue = new List<string>();
    lstCombxValue.Add("Item A1");
    //Item to Disable
    lstCombxValue.Add("Item A2");
    lstCombxValue.Add("Item A3");
    lstCombxValue.Add("Item A4");
    lstCombxValue.Add("Item A5");
    lstCombxValue.Add("Item A6");

    comboBox1.DataSource = lstCombxValue;
 }

 private void comboBox1_DrawItem(object sender, DrawItemEventArgs e)
 {
     //Check the Condition get the Item Index Value to Disable 
     //and follow this step to disable the item
     if (e.Index == 1)
     {
         e.Graphics.DrawString(comboBox1.Items[e.Index].ToString(), fontValue, Brushes.Gray, e.Bounds);
     }
     else
     {
         e.DrawBackground();
         e.Graphics.DrawString(comboBox1.Items[e.Index].ToString(), fontValue, Brushes.Black, e.Bounds);
         e.DrawFocusRectangle();
     }
 }