.Net平台Winform两个ComboBox控件绑定同一个数据源

今天WINFROM编程遇到这么一个问题：是有关WINFORM中两个comboBox控件绑定同一个数据源的问题，在窗体的界面上有两个comboBox，我在Form1_Load中对他们做了数据绑定（具体代码如下），但是运行出现了这个一个奇怪的问题，我改变了comboBox1的值，但是comboBox2的值也自动改变了，我没有设置comboBox1_SelectedIndexChanged函数

 1 private void Form1_Load(object sender, EventArgs e) 
 2 { 
 3 dataset ds=getds("select code,name from shp") ;
 4  
 5 comboBox1.DataSource = ds; 
 6 comboBox1.ValueMember = "code"; 
 7 comboBox1.DisplayMember = "name"; 
 8 comboBox1.SelectedIndex = 0; 
 9 
10 
11 comboBox2.DataSource = ds; 
12 comboBox2.ValueMember = "code"; 
13 comboBox2.DisplayMember = "name"; 
14 comboBox2.SelectedIndex = 0; 
15 }

解决方法：

 1 dataset ds=getds("select code,name from shp") 
 2 
 3 comboBox1.DataSource = ds; 
 4 comboBox1.ValueMember = "code"; 
 5 comboBox1.DisplayMember = "name"; 
 6 comboBox1.SelectedIndex = 0; 
 7 
 8 comboBox2.DataSource = ds.Copy(); 
 9 comboBox2.ValueMember = "code"; 
10 comboBox2.DisplayMember = "name"; 
11 comboBox2.SelectedIndex = 0;