DropDownList Database - asp.net

Question

I have a DB and a DropDownList, but this always only shows System.Data.DataRowView. What can I do? My code:
<asp:DropDownList ID="DropDownList1" runat="server" DataSourceID="SqlDataSource2">
</asp:DropDownList>
<asp:SqlDataSource ID="SqlDataSource2" runat="server" ConnectionString="<%$ ConnectionStrings:campingConnectionString2 %>" ProviderName="<%$ ConnectionStrings:campingConnectionString2.ProviderName %>" SelectCommand="SELECT Distinct LandDE FROM campingplatz ORDER BY LandDE ASC"></asp:SqlDataSource>

Answer 1

You need to set the DataTextField and DataValueField properties for the list, so it knows what columns in the DataRow to look at.

Answer 2

Ok, there are always quite a few ways to do this.
I often don't use a "datasource" imbeeded in the markup. They are often less then easy to deal with. (but, I'll often use the wizard to setup the dropdown, as it does setup the columns etc.
but, lets say we have two combo boxes. One for City, and then when you select the city then the 2nd combo box fills with hotels from that city.
So we have this markup:
<div style="font-size:x-large">
Select City:
<asp:DropDownList ID="cboCity" runat="server" width="150px" style="margin-right:25px"
DataValueField="City" DataTextField="City"
AutoPostBack="true" OnTextChanged="cboCity_TextChanged">
</asp:DropDownList>
Select Hotel:
<asp:DropDownList ID="cboHotels" runat="server" width="150px"
DataValueField="ID" DataTextField="HotelName">
</asp:DropDownList>
</div>
And then some code to fill the first combo box, and the 2nd one like this:
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Not IsPostBack Then
' load combo box (City)
Using cmdSQL As SqlCommand = New SqlCommand("SELECT City from tblCity ORDER BY City",
New SqlConnection(My.Settings.TEST3))
cmdSQL.Connection.Open()
cboCity.DataSource = cmdSQL.ExecuteReader
cboCity.DataBind()
' add blank row to combo
cboCity.Items.Insert(0, "")
End Using
End If
End Sub
Protected Sub cboCity_TextChanged(sender As Object, e As EventArgs)
' fill hotels combo based on city
Dim strSQL As String
strSQL = "SELECT ID, HotelName FROM tblHotels WHERE City = #City ORDER BY HotelName"
Using cmdSQL As SqlCommand = New SqlCommand(strSQL, New SqlConnection(My.Settings.TEST3))
cmdSQL.Parameters.Add("#City", SqlDbType.NVarChar).Value = cboCity.SelectedValue
cmdSQL.Connection.Open()
cboHotels.DataSource = cmdSQL.ExecuteReader
cboHotels.DataBind()
End Using
End Sub
So now we get say this:
So we did set autopostback = true for the first combo, and when the user selected the city, then we use that city value to fill the 2nd combo with a list of hotels from that city.

Answer 3

Unfortunately, I do not understand that. Can you do that on my code, please?
<asp:DropDownList ID="LandList" runat="server" DataSourceID="SqlDataSource2" AutoPostBack="True" DataMember="DefaultView" DataTextField="LandDE" DataValueField="LandDE">
</asp:DropDownList>
<asp:SqlDataSource ID="SqlDataSource2" runat="server" ConnectionString="<%$ ConnectionStrings:campingConnectionString2 %>" ProviderName="<%$ ConnectionStrings:campingConnectionString2.ProviderName %>" SelectCommand="SELECT Distinct LandDE FROM campingplatz ORDER BY LandDE ASC"></asp:SqlDataSource>