Binding to GridView

[Russ]

I'm thinking of purchasing your controls for an upcoming project but I am getting a couple of errors that I'm hoping you can help me with.  I have a sample project available.

1) The error below happens when I bind to the grid:

System.ArgumentException: An item with the same key has already been added.
   at System.ThrowHelper.ThrowArgumentException(ExceptionResource resource)
   at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)
   at System.Collections.Generic.Dictionary`2.Add(TKey key, TValue value)
   at Telerik.WinControls.UI.GridTableElement.GetRowStyleForType(String elementTypeFullName)
   at Telerik.WinControls.UI.GridTableElement.GetRowStyle(GridRowElement row)
   at Telerik.WinControls.UI.GridRowElement.GetRowStyle()
   at Telerik.WinControls.UI.GridRowElement.ApplyCustomFormatting()
   at Telerik.WinControls.UI.GridRowElement.UpdateInfo()
   at Telerik.WinControls.UI.GridTableBodyElement.UpdateState()
   at Telerik.WinControls.UI.GridTableElement.UpdateCurrentColumn()
   at Telerik.WinControls.UI.GridViewTemplate.SetCurrentColumn(GridViewColumn column, Boolean update, Boolean shift, Boolean control)
   at Telerik.WinControls.UI.GridViewTemplate.set_CurrentColumn(GridViewColumn value)
   at Telerik.WinControls.UI.GridTableElement.UpdateCurrentPosition()
   at Telerik.WinControls.UI.GridViewInfo.SetCurrentRow(GridViewRowInfo row, Boolean setPosition, Boolean shift, Boolean control, Boolean rightMouseButton)
   at Telerik.WinControls.UI.GridViewTemplate.SetCurrentRow(GridViewRowInfo rowInfo)
   at Telerik.WinControls.Data.DataAccessComponent.InitDataGrid()
   at Telerik.WinControls.Data.DataAccessComponent.Bind(Object dataSource, String dataMember)
   at Telerik.WinControls.Data.DataAccessComponent.set_DataSource(Object value)
   at WindowsApplication4.Form1.worker_DoWork(Object sender, DoWorkEventArgs e) in c:\devprojects\WindowsApplication4\WindowsApplication4\Form1.vb:line 14

2) The second error is Exception has been thrown by the target of an invocation.  There is no clear way to reproduce.  Sometimes it happens on startup, other times it me three or four clicks.
   at System.RuntimeMethodHandle._InvokeMethodFast(Object target, Object[] arguments, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks)
   at System.Delegate.DynamicInvokeImpl(Object[] args)
   at System.Windows.Forms.Control.InvokeMarshaledCallbackDo(ThreadMethodEntry tme)
   at System.Windows.Forms.Control.InvokeMarshaledCallbackHelper(Object obj)
   at System.Threading.ExecutionContext.runTryCode(Object userData)
   at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Windows.Forms.Control.InvokeMarshaledCallback(ThreadMethodEntry tme)
   at System.Windows.Forms.Control.InvokeMarshaledCallbacks()
   at System.Windows.Forms.Control.WndProc(Message& m)
   at Telerik.WinControls.RadControl.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
   at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
   at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
   at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.OnRun()
   at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.DoApplicationModel()
   at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.Run(String[] commandLine)
   at WindowsApplication4.My.MyApplication.Main(String[] Args) in 17d14f5c-a337-4978-8281-53493378c1071.vb:line 81
   at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args)
   at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.ThreadHelper.ThreadStart()

Please le tme know if you can help.

[Russ]

Here's the jist of the code

 

 

  Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
    With Me.worker
      .RunWorkerAsync()
    End With
  End Sub

  Private Sub worker_DoWork(ByVal sender As Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles worker.DoWork
    Try
      Using db As New DataClasses1DataContext
        db.Log = Console.Out
        Dim q = From c In db.GetTable(Of candidate)() _
                        Select c.candidate_num, c.first_name, c.last_name
        Me.RadGridView1.DataSource = q  ''This throws error #1 from the original post.  I believe this is the same line causing error #2 but I'm unsure
      End Using
    Catch ex As Exception
      Using sw As New System.IO.StreamWriter(My.Application.Info.DirectoryPath & "\LogFile.txt")
        sw.WriteLine(ex.ToString)
      End Using
    End Try
  End Sub
  Private Sub Clear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Clear.Click
    Me.RadGridView1.DataSource = Nothing
  End Sub

  Private Sub Load_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles LoadData.Click
    With Me.worker
      .RunWorkerAsync()
    End With
  End Sub

 

[Victor]

Hello Russ,

Thank you for writing.
 
RadControls are not thread safe. You must employ locking constructs and synchronization logic if you need to access the grid from another thread. This is why exceptions get thrown.
 
I have attached a sample application we prepared for another customer to demonstrate a way of doing this. It is in C#, but you can use this converter to convert the project code to VB in case you are not familiar with C#. Write again if you have other questions about our controls.

Best wishes,
Victor
the Telerik team

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