省市区三级如何设置初始值

[chen553152469]

#region 实现省市区三级
//数据绑定
private void BindPro()
{
using (SqlConnection con = new SqlConnection("server=.;database=lskj;uid=sa;pwd=sa"))
{
con.Open();

//初始化省

SqlCommand cmdPro = new SqlCommand("select ProvinceID,ProvinceName from S_Province", con);
SqlDataReader drPro = cmdPro.ExecuteReader();
this.ddlProvince.DataSource = drPro;
this.ddlProvince.DataTextField = "ProvinceName";
this.ddlProvince.DataValueField = "ProvinceID";
this.ddlProvince.DataBind();
drPro.Close();

//初始化市

SqlCommand cmdCity = new SqlCommand("select CityID,CityName from S_City where ProvinceID = " + this.ddlProvince.SelectedValue + "", con);
SqlDataReader drCity = cmdCity.ExecuteReader();
this.ddlCity.DataSource = drCity;
this.ddlCity.DataTextField = "CityName";
this.ddlCity.DataValueField = "CityID";
this.ddlCity.DataBind();
drCity.Close();
//初始化县

SqlCommand cmdDist = new SqlCommand("select DistrictID,DistrictName from S_District where DistrictID = " + this.ddlCity.SelectedValue + "", con);
SqlDataReader drDist = cmdDist.ExecuteReader();
this.ddlDist.DataSource = drDist;
this.ddlDist.DataTextField = "DistrictName";
this.ddlDist.DataValueField = "DistrictID";
this.ddlDist.DataBind();
drDist.Close();
}
}

protected void ddlProvince_SelectedIndexChanged(object sender, EventArgs e) //DropDownList选中（省改变）产生的事件
{
string ProvinceID = this.ddlProvince.SelectedValue;
using (SqlConnection con = new SqlConnection("server=.;database=lskj;uid=sa;pwd=sa;"))
{
con.Open();
SqlCommand cmdCity = new SqlCommand("select CityID,CityName from S_City where ProvinceID=" + ProvinceID + "", con);
SqlDataReader drCity = cmdCity.ExecuteReader();
this.ddlCity.DataSource = drCity;
this.ddlCity.DataTextField = "CityName";
this.ddlCity.DataValueField = "CityID";
this.ddlCity.DataBind();
this.ddlCity.Items.Insert(0,"-请选择-");
this.ddlCity.Items[0].Value = "0";
drCity.Close();
con.Close();
ddlCityBind();
}

}
protected void ddlCity_SelectedIndexChanged(object sender, EventArgs e)
{
ddlCityBind();
}

private void ddlCityBind()
{
string CityID = this.ddlCity.SelectedValue;
using (SqlConnection con = new SqlConnection("server=.;database=lskj;uid=sa;pwd=sa;"))
{
con.Open();
SqlCommand cmdDist = new SqlCommand("select DistrictID,DistrictName from S_District where CityID =" + CityID + "", con);
SqlDataReader drDist = cmdDist.ExecuteReader();
this.ddlDist.DataSource = drDist;
this.ddlDist.DataTextField = "DistrictName";
this.ddlDist.DataValueField = "DistrictID";
this.ddlDist.DataBind();
this.ddlDist.Items.Insert(0, "-请选择-");
this.ddlDist.Items[0].Value = "0";
drDist.Close();
}
}
#endregion

请问如何在页面的省市区里都显示“-请选择-”

[ysq453499415]

兄弟也可以用这个办法试试看
ListItem a = new ListItem("==请选择==", "0");
drp_user_Distribution.Items.Add(a);
drp_user_Distribution.SelectedIndex = 0;
if (ds != null && ds.Tables[0].Rows.Count != 0)
{
for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
{
ListItem item = new ListItem(ds.Tables[0].Rows[i]["username"].ToString(), ds.Tables[0].Rows[i]["Id"].ToString());
drp_user_Distribution.Items.Add(item);
drp_usersearch.Items.Add(item);
drp_user_Release.Items.Add(item);
}
}