VB.net DetailsView to use more than one datasource? - vb.net

Question

I have a DetailsView that looks just about perfect. The only thing is, there is one field that actually gets its information from another table. It is an ID field that is linked to another table in the database and I was hoping that there was some way to get that one field in the DetailsView to pull the information from the other table.
Is there a way to maybe add a + (plus sign) next to the PicklistID and then have it show the results of the other query? (SELECT TEXT FROM PICKLIST WHERE PicklistID = #PicklistID???)
UPDATE 1/11/12: The PICKLISTID in the table PICKLIST is not unique or a primary key so I cannot reference it from the SURVEY table. Is there a way to give these 2 columns a relationship so that I can just change my SELECT statement in my DetailsView to include the PICKLISTID?
UPDATE 1/23/12: I'm still stuck on this. I am not getting how to make this work at all. Help would be appreciated. I am still new....
<asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server">
<asp:Label ID="Label2" runat="server" Text="<h3>Manage Questions</h3>"></asp:Label>
<table style="width: 100%">
<tr>
<td align="right">
<asp:Label ID="Label1" runat="server" Text="Select Survey:"></asp:Label>
</td>
<td>
<asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="True"
DataSourceID="dsSurvey" DataTextField="SurveyName" DataValueField="SurveyID">
</asp:DropDownList>
</td>
</tr>
<tr>
<td colspan="2">
<asp:DetailsView ID="dvSurveyQuestions" runat="server" AllowPaging="True"
AutoGenerateRows="False" CellPadding="4" DataKeyNames="QuestionID"
DataSourceID="dsSurveyQuestions" ForeColor="#333333" GridLines="None"
Height="50px" Width="100%">
<FooterStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
<CommandRowStyle BackColor="#E2DED6" Font-Bold="True" />
<EditRowStyle BackColor="#999999" />
<RowStyle BackColor="#F7F6F3" ForeColor="#333333" />
<PagerStyle BackColor="#284775" ForeColor="White" HorizontalAlign="Center" />
<Fields>
<asp:BoundField DataField="QuestionID" HeaderText="QuestionID"
InsertVisible="False" ReadOnly="True" SortExpression="QuestionID" />
<asp:TemplateField HeaderText="Question" SortExpression="Question">
<EditItemTemplate>
<asp:TextBox ID="TextBox1" runat="server" TextMode="MultiLine"
Text='<%# Bind("Question") %>'></asp:TextBox>
</EditItemTemplate>
<InsertItemTemplate>
<asp:TextBox ID="TextBox1" runat="server" TextMode="MultiLine"
Text='<%# Bind("Question") %>'></asp:TextBox>
</InsertItemTemplate>
<ItemTemplate>
<asp:Label ID="lblQuestion" runat="server" Text='<%# Bind("Question") %>'>
</asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Answer Type" SortExpression="AnswerType">
<EditItemTemplate>
<asp:DropDownList ID="DropDownList2" runat="server"
SelectedValue='<%# Bind("AnswerType") %>'>
<asp:ListItem Value="S">Single Choice (radio button)</asp:ListItem>
<asp:ListItem Value="M">Multiple Choices (checkboxes)</asp:ListItem>
<asp:ListItem Value="T">Text (textbox)</asp:ListItem>
</asp:DropDownList>
</EditItemTemplate>
<InsertItemTemplate>
<asp:DropDownList ID="DropDownList3" runat="server"
SelectedValue='<%# Bind("AnswerType") %>'>
<asp:ListItem Value="S">Single Choice (radio button)</asp:ListItem>
<asp:ListItem Value="M">Multiple Choices (checkboxes)</asp:ListItem>
<asp:ListItem Value="T">Text (textbox)</asp:ListItem>
</asp:DropDownList>
</InsertItemTemplate>
<ItemTemplate>
<asp:Label ID="lblAnswerType" runat="server"
Text='<%# Bind("AnswerType") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Question Type" SortExpression="QType">
<EditItemTemplate>
<asp:DropDownList ID="DropDownList4" runat="server"
SelectedValue='<%# Bind("QType") %>'>
<asp:ListItem Value="Picklist">Picklist</asp:ListItem>
<asp:ListItem Value="Text">Text</asp:ListItem>
</asp:DropDownList>
</EditItemTemplate>
<InsertItemTemplate>
<asp:DropDownList ID="DropDownList5" runat="server"
SelectedValue='<%# Bind("QType") %>'>
<asp:ListItem Value="Picklist">Picklist</asp:ListItem>
<asp:ListItem Value="Text">Text</asp:ListItem>
</asp:DropDownList>
</InsertItemTemplate>
<ItemTemplate>
<asp:Label ID="lblQType" runat="server" Text='<%# Bind("QType") %>'>
</asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Answer" SortExpression="TEXT">
<EditItemTemplate>
</EditItemTemplate>
<InsertItemTemplate>
</InsertItemTemplate>
<ItemTemplate>
<asp:HiddenField ID="HiddenField1" runat="server" Value='<%# Bind("PicklistID") %>' />
<asp:SqlDataSource ID="dsPicklist" runat="server"
ConnectionString="<%$ ConnectionStrings:SurveyConnectionString %>"
SelectCommand="SELECT DISTINCT p.TEXT, p.PICKLISTID
FROM PICKLIST p JOIN C_Survey_Questions c
ON c.PicklistID = p.PICKLISTID
AND c.SurveyID = #SurveyID
ORDER BY p.TEXT">
<SelectParameters>
<asp:ControlParameter ControlID="HiddenField1" Name="PicklistID"
PropertyName="SelectedValue" Type="String" />
</SelectParameters>
</asp:SqlDataSource>
<asp:Label ID="lblTEXT" runat="server" Text=""></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:BoundField DataField="QuestionNum" HeaderText="Question Number"
SortExpression="QuestionNum" />
<asp:BoundField DataField="Subsequence" HeaderText="Subsequence"
SortExpression="Subsequence" />
<asp:CheckBoxField DataField="Active" HeaderText="Active"
SortExpression="Active" />
<asp:BoundField DataField="Script" HeaderText="Script"
SortExpression="Script" />
<asp:CheckBoxField DataField="Question_Locked" HeaderText="Question Locked"
SortExpression="Question_Locked" />
<asp:BoundField DataField="QHelp" HeaderText="Question Help"
SortExpression="QHelp" />
<asp:CommandField ShowDeleteButton="True" ShowEditButton="True"
ShowInsertButton="True" />
</Fields>
<FieldHeaderStyle BackColor="#E9ECF1" Font-Bold="True" Width="10%" />
<HeaderStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
<AlternatingRowStyle BackColor="White" ForeColor="#284775" />
</asp:DetailsView>
</td>
</tr>
</table>
<asp:SqlDataSource ID="dsSurvey" runat="server"
ConnectionString="<%$ ConnectionStrings:SurveyConnectionString %>"
SelectCommand="SELECT [SurveyID], [SurveyName]
FROM [C_Survey]
ORDER BY [SurveyName]">
</asp:SqlDataSource>
<asp:SqlDataSource ID="dsSurveyQuestions" runat="server"
ConnectionString="<%$ ConnectionStrings:SurveyConnectionString %>"
DeleteCommand="DELETE FROM [C_Survey_Questions] WHERE [QuestionID] = #QuestionID"
InsertCommand="INSERT INTO [C_Survey_Questions] ([SurveyID], [Question], [QType],
[PickListID], [QuestionNum], [Subsequence], [Active], [Script],
[Question_Locked], [QHelp], [Createdate],
[Modifydate], [AnswerType])
VALUES (#SurveyID, #Question, #QType, #PickListID, #QuestionNum,
#Subsequence, #Active, #Script, #Question_Locked, #QHelp,
getdate(), getdate(), #AnswerType)"
SelectCommand="SELECT * FROM [C_Survey_Questions]
WHERE ([SurveyID] = #SurveyID)"
UpdateCommand="UPDATE [C_Survey_Questions] SET [SurveyID] = #SurveyID,
[Question] = #Question, [QType] = #QType,
[PickListID] = #PickListID, [QuestionNum] = #QuestionNum,
[Subsequence] = #Subsequence, [Active] = #Active,
[Script] = #Script, [Question_Locked] = #Question_Locked,
[QHelp] = #QHelp, [Modifydate] = getdate(),
[AnswerType] = #AnswerType
WHERE [QuestionID] = #QuestionID">
<DeleteParameters>
<asp:Parameter Name="QuestionID" Type="Int32" />
</DeleteParameters>
<InsertParameters>
<asp:Parameter Name="SurveyID" Type="Int32" />
<asp:Parameter Name="Question" Type="String" />
<asp:Parameter Name="QType" Type="String" />
<asp:Parameter Name="PickListID" Type="String" />
<asp:Parameter Name="QuestionNum" Type="Int32" />
<asp:Parameter Name="Subsequence" Type="Int32" />
<asp:Parameter Name="Active" Type="Boolean" />
<asp:Parameter Name="Script" Type="String" />
<asp:Parameter Name="Question_Locked" Type="Boolean" />
<asp:Parameter Name="QHelp" Type="String" />
<asp:Parameter Name="Createdate" Type="DateTime" />
<asp:Parameter Name="Modifydate" Type="DateTime" />
<asp:Parameter Name="AnswerType" Type="String" />
</InsertParameters>
<SelectParameters>
<asp:ControlParameter ControlID="DropDownList1" Name="SurveyID"
PropertyName="SelectedValue" Type="Int32" />
</SelectParameters>
<UpdateParameters>
<asp:Parameter Name="SurveyID" Type="Int32" />
<asp:Parameter Name="Question" Type="String" />
<asp:Parameter Name="QType" Type="String" />
<asp:Parameter Name="PickListID" Type="String" />
<asp:Parameter Name="QuestionNum" Type="Int32" />
<asp:Parameter Name="Subsequence" Type="Int32" />
<asp:Parameter Name="Active" Type="Boolean" />
<asp:Parameter Name="Script" Type="String" />
<asp:Parameter Name="Question_Locked" Type="Boolean" />
<asp:Parameter Name="QHelp" Type="String" />
<asp:Parameter Name="Modifydate" Type="DateTime" />
<asp:Parameter Name="AnswerType" Type="String" />
<asp:Parameter Name="QuestionID" Type="Int32" />
</UpdateParameters>
</asp:SqlDataSource>
</asp:Content>
Partial Class Admin_ManageQuestions
Inherits System.Web.UI.Page
Protected Sub dsPicklist_ItemSelecting(ByVal sender As Object, ByVal e As
System.EventArgs) Handles Me.Load
Dim myControl1 As Control = FindControl("lblTEXT")
If (Not myControl1 Is Nothing) Then
myControl1.DataBind()
Else
'Control not found
End If
End Sub
Protected Sub dvSurveyQuestions_ItemInserting(ByVal sender As Object, ByVal e As
System.Web.UI.WebControls.DetailsViewInsertEventArgs) Handles
dvSurveyQuestions.ItemInserting
'The DetailsView does not include SurveyID column...we need to set this column
during INSERT operations because each question must belong to some survey.
e.Values("SurveyID") = DropDownList1.SelectedValue
End Sub
Protected Sub dvSurveyQuestions_ItemUpdating(ByVal sender As Object, ByVal e As
System.Web.UI.WebControls.DetailsViewUpdateEventArgs) Handles
dvSurveyQuestions.ItemUpdating
'The DetailsView does not include SurveyID column...we need to set this column
during UPDATE operations because each question must belong to some survey.
e.NewValues("SurveyID") = DropDownList1.SelectedValue
End Sub
Protected Sub dvSurveyQuestions_DataBound(ByVal sender As Object, ByVal e As
System.EventArgs) Handles dvSurveyQuestions.DataBound
'The event handler checks the row count of the DetailsView control.
If it is zero then the mode of the DetailsView is changed to Insert using
ChangeMode() method.
If dvSurveyQuestions.Rows.Count = 0 Then
dvSurveyQuestions.ChangeMode(DetailsViewMode.Insert)
End If
End Sub
End Class

Answer 1

You can do that, but maybe not in the way you want to.
The simplest way would be to use the DataBinding event on the DetailsView itself. Then use code to run the query.
Another way would be to create your own control as a subclass of BoundField and override the OnDataBindField method
The most performant way would be to join the data at the source in a DataView or another construct. Ideally the joining of data should be done as close to the actual source of the data (e.g. in a SQL query or view) to avoid unnecessary trips across the network to the database. For a single row it wouldn't be a big issue, but that is generally what you should do.