asp.net 控件样式问题

Question

如何更改DropDownList 右边的下拉三角按钮颜色

Answer 1

 protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
    {
        string color = this.DropDownList1.SelectedItem.Value;
        switch (color) 
        {
            case "Red":
                this.DropDownList1.BackColor = System.Drawing.Color.Red;
                break;
            case "Green":
                this.DropDownList1.BackColor = System.Drawing.Color.Green;
                break;
            case "Blue":
                this.DropDownList1.BackColor = System.Drawing.Color.Blue;
                break;
            case "LightGray":
                this.DropDownList1.BackColor = System.Drawing.Color.LightGray;
                break;
            default :
                this.DropDownList1.BackColor = System.Drawing.Color.White;
                break;
        }
    }