DropDownList 和Combox 数据绑定的常用方法

web DropDownList绑定数据源的几种方式
第一种
this.ddltype.DataTextField = "btName";//显示的值
this.ddltype.DataValueField = "btId";//获取dropdownlist中的值
ddltype.DataSource = service.GetBusinessTypeAll("");
this.ddltype.DataBind();
第二种
DataTable dt_GetBusinessName = service.GetBusinessTypeAll("");

//表中无数据的话直接返回
if (dt_GetBusinessName == null)
return;

for (int i = 0; i < dt_GetBusinessName.Rows.Count; i++)
{
ddltype.Items.Add(new ListItem(dt_GetBusinessName.Rows[i]["btName"].ToString().Trim(),//显示的值
dt_GetBusinessName.Rows[i]["btId"].ToString().Trim()));
}s
ddltype.Items.Add(new ListItem("全部", "-1"));
ddltype.Text = "全部";

如何选中DropDownList1中的值用

protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
this.TextBox1.Text = this.DropDownList1.SelectedItem.Text.ToString();
}

windows combox的手写数据绑定
第一种：
cCombox1.DisplayMember = "btName";//显示的值
cCombox1.ValueMember = "btId";
cCombox1.DataSource = _manageService.GetBusinessTypeAll(this.UserInfo.uNote1);
第二种：
DataTable dt_GetStateByName = _financeService.GetStateByNam(UserInfo.uNote1);

//表中无数据的话直接返回
if (dt_GetStateByName == null)
return;

for (int i = 0; i < dt_GetStateByName.Rows.Count; i++)
{
cbType2.Items.Add(new ListItem(dt_GetStateByName.Rows[i]["osState"].Trim(),
dt_GetStateByName.Rows[i]["osName"].ToString().Trim()));//显示的值
}
cbType2.Items.Add(new ListItem("-1", "全部"));
cbType2.Text = "全部";