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ASP.NET 2.0 Basics If you are new to ASP or ASP.NET programming with version 2.0, this is the forum to begin asking questions. Please also see the Visual Web Developer 2005 forum.
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  #11 (permalink)  
Old December 1st, 2005, 05:46 PM
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No, there is only a "null" value. I want to replace the "null" value with one from the DropDownList.

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Old December 1st, 2005, 06:28 PM
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Right, that explains a lot.

null is not a valid value in the DropDownList so you can't use that as a value for the SelectedValue property.

You should implement some code for the DataBound event of the DetailsView control. Inside that event handler, get a reference to the View's DataItem which by default is a DataRowView when you're using a default SqlDataSource. Then get the value from the column in the DataRowView, see if it's not null and see if you can find it in the DropDownList. The following should work:
Code:
Protected Sub DetailsView1_DataBound(ByVal sender As Object, ByVal e As System.EventArgs) _
          Handles DetailsView1.DataBound
    Select Case DetailsView1.CurrentMode
      Case DetailsViewMode.Edit
        Dim myDataRowView As DataRowView = DetailsView1.DataItem
        If myDataRowView("Description") IsNot DBNull.Value Then
          Dim myDropDownList As DropDownList = _ 
         CType(DetailsView1.FindControl("DropDownList1"), DropDownList)
          If myDropDownList.Items.FindByValue(myDataRowView("Description")) _
         IsNot Nothing Then
            myDropDownList.Items.FindByValue(myDataRowView("Description")).Selected = True
          End If
        End If
    End Select
  End Sub
  There might be more efficient ways to do this though....
They say about .NET that it makes difficult things easy, and easy things difficult. I don't think that has changed much for .NET 2.0.... ;)


Hope this helps,

Imar
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Old December 1st, 2005, 06:39 PM
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Oh, BTW, probably a *lot* easier is this:
<asp:DropDownList .....>
  <asp:ListItem Value="">Please select an color</asp:ListItem>
</asp:DropDownList>

Just insert a default item in the drop-down list that has a value of "". Then use a RequiredFieldValidator to force the user to make a new selection when editing an existing item that has a null value in the database.

Cheers,

Imar


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Old December 1st, 2005, 06:42 PM
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Imar, I'm at work right now until 3 am, so I can't try the code until I get home. I hope it works and will post whether it does or not. Where do I learn about writing code like that? Would a VB book be a solution?

Thanks for all your help and I'll let you know if it works!

Greg

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Old December 1st, 2005, 06:52 PM
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I am working on a book about ASP.NET 2,0 right now, scheduled for release in March ;)

If you can't wait that long, I think Professional ASP.NET 2.0 should cover topics like these. Beware: I haven't read nor seen that book yet, so I can't guarantee it covers these kind of topics.

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Old December 11th, 2005, 01:49 PM
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Hey, I finally figured it out! I didn't have to implement any code. In the UpdateParameters collection for the Parameter "Color", I added the line: ConvertEmptyStringToNull="false" and it works like a champ! NO CODE to make it work. Thanks for the help.

Greg

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Old August 10th, 2006, 09:05 AM
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Hi Guy's

I am not sure if your are interacting with a SQL server 2005 Express database like I was but I got the same error it was because I had by Data Types as nchar(20) which is not a variable when it should have been varchar(20) or nvarchar(20) which every you need heres a link for it

http://www.databasejournal.com/featu...e.phpr/2212141

Lookly I identified the problem quick, its a stupid mistake and considering I did hell of a lot of database modules at uni I should shoot myself!

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Old June 7th, 2007, 04:54 PM
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I am also pulling out my hair with this!!


Author, SharpDeveloper.NET
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