.Net平台Winform兩個ComboBox控件綁定同一個數據源

今天WINFROM編程遇到這么一個問題：是有關WINFORM中兩個comboBox控件綁定同一個數據源的問題，在窗體的界面上有兩個comboBox，我在Form1_Load中對他們做了數據綁定（具體代碼如下），但是運行出現了這個一個奇怪的問題，我改變了comboBox1的值，但是comboBox2的值也自動改變了，我沒有設置comboBox1_SelectedIndexChanged函數

private void Form1_Load(object sender, EventArgs e)
{
dataset ds=getds("select code,name from shp") ;

comboBox1.DataSource = ds;
comboBox1.ValueMember = "code";
comboBox1.DisplayMember = "name";
comboBox1.SelectedIndex = 0;

comboBox2.DataSource = ds;
comboBox2.ValueMember = "code";
comboBox2.DisplayMember = "name";
comboBox2.SelectedIndex = 0;
}

解決方法：

dataset ds=getds("select code,name from shp")

comboBox1.DataSource = ds;
comboBox1.ValueMember = "code";
comboBox1.DisplayMember = "name";
comboBox1.SelectedIndex = 0;

comboBox2.DataSource = ds.Copy();
comboBox2.ValueMember = "code";
comboBox2.DisplayMember = "name";
comboBox2.SelectedIndex = 0;