winform下combobox奇怪的问题！！！！！！！！！！！！！！

[gxkgxkgxk]

comboBox2.Items.Clear();

DataTable dt3 = new DataTable("table");
DataColumn dc1 = new DataColumn("id", typeof(int));
DataColumn dc2 = new DataColumn("name", typeof(string));
dt3.Columns.Add(dc1);
dt3.Columns.Add(dc2);

for(int i = 0; i < dt.Rows.Count; i++)
{
DataRow dr = dt3.NewRow();
dr["id"] = dt.Rows[i]["Uid"];
dr["name"] = dt.Rows[i]["Name"].ToString();;
dt3.Rows.Add(dr);
}


this.comboBox2.DataSource = dt3;
this.comboBox2.DisplayMember = "name";
this.comboBox2.ValueMember = "id";
this.comboBox2.SelectedValue=dt.Rows[0]["Uid"];


我用如下的方式增加了comboxbox 的条目
然后private void comboBox2_SelectedIndexChanged(object sender, System.EventArgs e)
{

//MessageBox.Show("'" + this.comboBox2.SelectedValue +"'");
string strSql = "SELECT * FROM checkItem where ClassId=" + this.comboBox2.SelectedValue + "";

if(this.comboBox2.SelectedValue.ToString().CompareTo("System.Data.DataRowView")==0)
{


}
else
{
dt2 = dbProviders.sqlProvider.ExecuteTable(strSql);
}


dataGrid1.DataSource=dt2;

}

这样来根据combobox的选择来填充GRID，为什么这段程序在form_load事件里会执行，然后this.comboBox2.SelectedValue的值是System.Data.DataRowView，为什么会出现这样的问题，我不得已就加了个判断，这是什么问题呢

[gxkgxkgxk]

up

[深山老翁]

楼主看这样得不得(未测试过)：
this.comboBox2.SelectedValue = (DataRowView)(dt.Rows[0]["Uid"]);