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[英]Dynamically populating a dropdownlist based on selected value in another dropdown list
[英]error populating dropdown list based on another dropdown list ID
我有两个下拉列表,第二个基于第一个的选定值进行填充。 这就是我填充第二个下拉列表的方式,但是它不是基于第一个中的所选项目填充的,这导致我更改了我的填充方式。
之前:
<asp:DropDownList ID="RootDropDown" runat="server" AutoPostBack="True" DataSourceID="FirstChild" DataTextField="DisplayName" DataValueField="ID"></asp:DropDownList>
<asp:SqlDataSource ID="FirstChild" runat="server" ConnectionString="<%$ ConnectionStrings:MyConnection %>" SelectCommand="SELECT e.DisplayName, e.ID , e.GUID
FROM SomeTable e
INNER JOIN TabletoTableMap em
ON e.ID = em.OtherTableID
WHERE em.SomeTableID = 9"+ ></asp:SqlDataSource>
后:
<asp:DropDownList ID="RootDropDown" runat="server" AutoPostBack="True" DataSourceID="FirstChild" DataTextField="DisplayName" DataValueField="ID" OnSelectedIndexChanged="Child"></asp:DropDownList>
子方法:
protected void Child(object sender, EventArgs e)
{
String strConnection = "Data Source=.;Initial Catalog=ALE;Integrated Security=True";
int RootID = Convert.ToInt32(CourseDropDown.SelectedValue);
System.Data.SqlClient.SqlConnection con = new System.Data.SqlClient.SqlConnection(strConnection);
con.Open();
System.Data.SqlClient.SqlCommand cmd = new System.Data.SqlClient.SqlCommand("SELECT e.DisplayName, e.ID , e.GUID FROM SomeTable e INNER JOIN TabletoTableMap em ON e.ID = em.OtherTableID WHERE em.SomeTableID="+RootID, con);
System.Data.SqlClient.SqlDataAdapter da = new System.Data.SqlClient.SqlDataAdapter(cmd);
System.Data.DataSet ds = new System.Data.DataSet();
da.Fill(ds);
con.Close();
RootElementDropDown.DataSourceID = "FirstChild";
RootElementDropDown.DataTextField = "DisplayName";
RootElementDropDown.DataValueField = "ID";
RootElementDropDown.DataBind();
}
错误:
The DataSourceID of 'RootDropDown' must be the ID of a control of type IDataSource. A control with ID 'FirstChild' could not be found.
尝试设置
DataMember as what you want
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