实现功能：  
         datatable绑定comboBox,在下拉菜单中显示对应数据  
    实现方法：  
         1、生成datatable，并为combox绑定数据源：  
                comboBox1.DataSource = dt1;  
                comboBox1.DisplayMember = "用户编码";  
                comboBox1.ValueMember = "ID";  
                this.comboBox1.SelectedIndex = -1;  
        2、在combox的SelectedIndexChanged事件中添加如下方法：  
            private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)  
            {  
                int iCurrentIndex = this.comboBox1.SelectedIndex;  
                if (iCurrentIndex < 0) return;  
                DataRow dr = dt1.Rows[iCurrentIndex];  
                iID = Int32.Parse(dr["ID"].ToString());  
            }  
    另：如果textBox也想绑定该数据源，实现连动（如输入编码显示对应名称）  
        3、在textBox的TextChanged事件中添加如下方法：  
            private void textBox1_TextChanged(object sender, EventArgs e)  
            {  
                string strUserNo = this.textBox1.Text.Trim();  
                for (int i = 0; i < dt1.Rows.Count; i++)  
                {  
                    if (dt1.Rows[i]["用户编码"].ToString() == strUserNo)  
                    {  
                        this.comboBox1.SelectedIndex = i;  
                        break;  
                    }  
                    else  
                    {  
                        this.comboBox1.SelectedIndex = -1;  
                    }  
                }  
            }