私はこのコードを実行するときに苦労していますが、このエラーが発生します。右この上記VB.net NullReferenceExeptionが処理されていません
IF (CheckedItem Is Nothing) Then
Next 'Or the VB version of the C# continue keyword (my VB is rusty)
:あなたはこれを挿入する必要があるよう
Dim CheckedItems(clbfiles.CheckedItems.Count) As Object
clbfiles.CheckedItems.CopyTo(CheckedItems, 0)
For Each CheckedItem As Object In CheckedItems
Dim FileToDelete As String
If Not CheckedItem.ToString = "" Then <---- error
'creates path to delete
FileToDelete = appdata + "\" + CheckedItem.ToString
If System.IO.File.Exists(FileToDelete) = True Then
'deletes
System.IO.File.Delete(FileToDelete)
MsgBox("File Deleted")
End If
'removes from list
clbfiles.Items.Remove(CheckedItem)
End If
Next
End Sub
エラーコード
System.NullReferenceException was unhandled
Message=Object reference not set to an instance of an object.
Source=ScreenShotCraft
StackTrace:
at ScreenShotCraft.frmindex.btndeleteselected_Click(Object sender, EventArgs e)
at System.Windows.Forms.Control.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ButtonBase.WndProc(Message& m)
at System.Windows.Forms.Button.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(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(IntPtr 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 ScreenShotCraft.My.MyApplication.Main(String[] Args)
at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()
InnerException:
これも重要な安全チェックです。私の答えは今日のバグがあった理由ですが、これは将来のバグを防ぐための答えです。 – mattmc3