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08.01.2008 at 12:49PM PDT, ID: 23615232
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8.5

SQL Parameter not supplied when ComboBox drop down style changed to DropDownList

Asked by ML-Huff in Visual Studio, Microsoft Visual Basic.Net, SQL Server 2005

Tags:

Working in Visual Studio Pro 2008, I have a form with several TextBoxes and ComboBoxes used for entering data into a SQL Server 2005 database.  I have created the update statement in code and it works fine for ALL fields as long as the ComboBoxes have their Drop Down List Style set to DropDown.  However, this would allow users to type values into the drop downs.  I would like to use the DropDownList of these ComboBoxes for data validation on certain fields.  So, I need to change the Drop Down Style to DropDownList.  But, whenever I do this the SQL update command fails with an error that says the parameter for that ComboBox was not supplied.  The data bindings are still set correctly, and I don't have to change anything else except for the Drop Down Style to get the SQL update command to work.  I'm stumped!!

I have attached some code that works as long as the ComboBox for Dept has its Drop Down Style set to DropDown.  When I set it to DropDownList, the NewVehicle.Dept property is set to nothing and the parameter is not supplied to the SQL update statement.Start Free Trial 
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Dim updateStatement As String = "UPDATE Vehicles SET " _
       	& "UnitID = @NewUnitID, " _
       	& "Dept = @NewDept" _
	& "Where " _
 	& "UnitID = @OldUnitID " _
	& "Dept = @OldDept"
 
   Dim updateCommand As New SqlCommand(updateStatement, FleetConnection)
   
   updateCommand.Parameters.AddWithValue("@NewUnitID", NewVehicle.UnitID)
   updateCommand.Parameters.AddWithValue("@NewDept", NewVehicle.Dept)
   updateCommand.Parameters.AddWithValue("@OldUnitID", OldVehicle.UnitID)
   updateCommand.Parameters.AddwithValue("@OldDept", OldVehicle.Dept)
 
   Try
       FleetConnection.Open()
       Dim count As Integer = updateCommand.ExecuteNonQuery
       If count > 0 Then
           Return True
       Else
           Return False
       End If
   Catch ex As Exception
       Throw ex
   Finally
       FleetConnection.Close()
   End Try
[+][-]08.01.2008 at 12:58PM PDT, ID: 22141504

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[+][-]08.01.2008 at 01:05PM PDT, ID: 22141545

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[+][-]08.01.2008 at 01:08PM PDT, ID: 22141567

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About this solution

Zones: Visual Studio, Microsoft Visual Basic.Net, SQL Server 2005
Tags: Visual Basic
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Solution Provided By: DanielWilson
Participating Experts: 1
Solution Grade: A
 
 
 
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