C# GUI keeps crashing due to System.InvalidCastException, when I press the button

Question

I'm trying to write my own GUI for a Program in C#, which translate Morsecode to text. My IDE doesn't show any errors and the GUI works so far. But when I push the button, for the translation of the text, the whole program crashes. I already reviewed my code, but I can't find any issues, because the IDE can build the program, without showing errors.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Runtime.CompilerServices;
using Morse.Annotations;
using Morse.Command;

namespace Morse.ViewModel
{
    public class MorseViewModel: INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;

        public MorseViewModel()
        {

            @UComm = new MorseCommand(this);
        }

        public Dictionary<char, string> MorseCode { get; set; }

        private string _meinTextWert;

        private string _meinErgebnisWert;

        public string MeinTextWert
        {
            get { return _meinTextWert;}
            set
            {
                if(value == _meinTextWert) return;
                _meinTextWert = value;
                OnPropertyChanged();
            }
        }

        public string MeinErgebnisWert
        {
            get { return _meinErgebnisWert; }
            set
            {
                if(value == _meinErgebnisWert) return;
                _meinErgebnisWert = value;
                OnPropertyChanged();
            }
        }

        public MorseCommand UComm { get; set; }

        [NotifyPropertyChangedInvocator]
        protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

This is my .xaml code for the GUI:

<TextBox Grid.Column="1" Grid.Row="1" Text="{Binding MeinTextWert}"
                MinWidth="250" HorizontalAlignment="Left" TextWrapping="NoWrap" AcceptsReturn="True" VerticalScrollBarVisibility="Auto"/>
        <TextBox Grid.Column="3" Grid.Row="1" Text="{Binding MeinErgebnisWert, UpdateSourceTrigger=PropertyChanged}"
                 MinWidth="250" HorizontalAlignment="Left" TextWrapping="NoWrap" AcceptsReturn="True" VerticalScrollBarVisibility="Auto"/>

<Button Grid.Column="1" Grid.Row="3" MinWidth="250" Command="{Binding UComm}"
                HorizontalAlignment="Center" Content="Übersetzen ins Morse" Padding="0.5"/>

And this is my Code for my ButtonCommand:

using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Input;
using Morse.ViewModel;

namespace Morse.Command
{
    public class MorseCommand: ICommand
    {
        private readonly MorseViewModel _morseViewModel;
        public MorseCommand(MorseViewModel morseViewModel)
        {
            _morseViewModel = morseViewModel;
        }

        public bool CanExecute(object parameter)
        {
            return true;
        }




        public void Execute(object parameter)
        {

            /*_morseViewModel.MeinTextWert = "test";*/

            Dictionary<char, string> MorseCode = new Dictionary<char, string>() {

                {'a', ".-"}, {'b', "-..."}, {'c', "-.-."}, {'d', "-.."}, {'e', "."},

                {'f', "..-."}, {'g', "--."}, {'h', "...."}, {'i', ".."}, {'j', ".---"},

                {'k', "-.-"}, {'l', ".-.."}, {'m', "--"}, {'n', "-."}, {'o', "---"},

                {'p', ".--."}, {'q', "--.-"}, {'r', ".-."}, {'s', "..."}, {'t', "-"},

                {'u', "..-"}, {'v', "...-"}, {'w', ".--"}, {'x', "-..-"}, {'y', "-.--"},

                {'z', "--.."}, {'0', "-----"}, {'1', ".----"}, {'2', "..---"},

                {'3', "...--"}, {'4', "....-"}, {'5', "....."}, {'6', "-...."},

                {'7', "--..."}, {'8', "---.."}, {'9', "----."}, {'à', ".--.-"},

                {'å', ".--.-"}, {'ä', ".-.-"}, {'è', ".-..-"}, {'é', "..-.."},

                {'ö', "---."}, {'ü', "..--"}, {'ß', "...--.."}, {'ñ', "--.--"},

                {'.', ".-.-.-"}, {',', "--..--"}, {':', "---..."}, {';', "-.-.-."},

                {'?', "..--.."}, {'-', "-....-"}, {'_', "..--.-"}, {'(', "-.--."},

                {')', "-.--.-"}, {'\'', ".----."}, {'=', "-...-"}, {'+', ".-.-."},

                {'/', "-..-."}, {'@', ".--.-."}, {' ', "   "}

            };

            StringBuilder Ausgabe  =new StringBuilder();

            char EingabeTextBox;

            EingabeTextBox = Convert.ToChar(_morseViewModel.MeinTextWert.ToLower().ToCharArray());


            for (int i = 0; i < _morseViewModel.MeinTextWert.Length ; i++)
            {
                if (i % 20 == 0)
                    Ausgabe.Append('\n');
                try
                {
                    Ausgabe.Append(MorseCode[_morseViewModel.MeinTextWert[i]]).Append(' ');
                }
                catch (KeyNotFoundException)
                {

                }

                _morseViewModel.MeinErgebnisWert = "\n Morse" + Ausgabe;

            }
        }

        public event EventHandler CanExecuteChanged;
    }
}```

I don't really get any errors in my EventLog. These are alle the logs I got:

23.03.2020 15:09 Build succeeded with warnings at 15:09:27

15:48 Build succeeded with warnings at 15:48:05

15:58 Build succeeded with warnings at 15:58:07

15:58 Build succeeded at 15:58:25

15:59 Build succeeded at 15:59:19

16:04 Build succeeded at 16:04:33```

These are the warnings in Errors In Solution.

I also debugged the program, and this is the Error I finally got:




System.InvalidCastException: Das Objekt des Typs "System.Char[]" kann nicht in Typ "System.IConvertible" umgewandelt werden.
   bei System.Convert.ToChar(Object value)
   bei Morse.Command.MorseCommand.Execute(Object parameter) in D:\Schule_Ordner\13. Klasse\Morse\Morse\Command\MorseCommand.cs:Zeile 66.
   bei MS.Internal.Commands.CommandHelpers.CriticalExecuteCommandSource(ICommandSource commandSource, Boolean userInitiated)
   bei MS.Internal.Commands.CommandHelpers.ExecuteCommandSource(ICommandSource commandSource)
   bei System.Windows.Controls.Primitives.ButtonBase.OnClick()
   bei System.Windows.Controls.Button.OnClick()
   bei System.Windows.Controls.Primitives.ButtonBase.OnMouseLeftButtonUp(MouseButtonEventArgs e)
   bei System.Windows.UIElement.OnMouseLeftButtonUpThunk(Object sender, MouseButtonEventArgs e)
   bei System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)
   bei System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
   bei System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
   bei System.Windows.RouteItem.InvokeHandler(RoutedEventArgs routedEventArgs)
   bei System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
   bei System.Windows.EventRoute.ReInvokeHandlers(Object source, RoutedEventArgs args)
   bei System.Windows.UIElement.ReRaiseEventAs(DependencyObject sender, RoutedEventArgs args, RoutedEvent newEvent)
   bei System.Windows.UIElement.CrackMouseButtonEventAndReRaiseEvent(DependencyObject sender, MouseButtonEventArgs e)
   bei System.Windows.UIElement.OnMouseUpThunk(Object sender, MouseButtonEventArgs e)
   bei System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)
   bei System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
   bei System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
   bei System.Windows.RouteItem.InvokeHandler(RoutedEventArgs routedEventArgs)
   bei System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
   bei System.Windows.EventRoute.InvokeHandlers(Object source, RoutedEventArgs args)
   bei System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
   bei System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args)
   bei System.Windows.UIElement.RaiseEvent(RoutedEventArgs args, Boolean trusted)
   bei System.Windows.Input.InputManager.ProcessStagingArea()
   bei System.Windows.Input.InputManager.ProcessInput(InputEventArgs input)
   bei System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport)
   bei System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawMouseActions actions, Int32 x, Int32 y, Int32 wheel)
   bei System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd, WindowMessage msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   bei System.Windows.Interop.HwndSource.InputFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   bei MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   bei MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
   bei System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   bei System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)
   bei System.Windows.Threading.Dispatcher.WrappedInvoke(Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)
   bei System.Windows.Threading.Dispatcher.LegacyInvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
   bei System.Windows.Threading.Dispatcher.Invoke(DispatcherPriority priority, Delegate method, Object arg)
   bei MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
   bei MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)
   bei System.Windows.Threading.Dispatcher.TranslateAndDispatchMessage(MSG& msg)
   bei System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
   bei System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)
   bei System.Windows.Threading.Dispatcher.Run()
   bei System.Windows.Application.RunDispatcher(Object ignore)
   bei System.Windows.Application.RunInternal(Window window)
   bei System.Windows.Application.Run(Window window)
   bei System.Windows.Application.Run()
   bei Morse.App.Main()

We usually need to know which line is throwing the exception, and post your error message, stack trace, ect. — LarsTech, Mar 23 '20 at 14:38
I assume there's a crash message. In addition to what @LarsTech says, the message gives details on the crash (like whether it's a null pointer exception, etc). — lurker, Mar 23 '20 at 14:43
The term "keeps crashing" is too broad, try editing your question and describing better the behaviour, error messages, etc... — Cleptus, Mar 23 '20 at 14:45
_"I already reviewed my code, but I can't find any issues, because the IDE can build the program, without showing errors"_ - if there were never any errors because the code compiles then SO would not exist. Have you tried debugging your code - put a breakpoint in the button event & step through. — PaulF, Mar 23 '20 at 14:48
Not sure this line is making a whole lot of sense: `char EingabeTextBox = Convert.ToChar(_morseViewModel.MeinTextWert.ToLower().ToCharArray());` — LarsTech, Mar 23 '20 at 14:55
My goto tool for things like this is "[break on exception](https://www.jetbrains.com/help/rider/Debugging_Exceptions.html#)" feature. This stops execution when the failure occurs, and allows you to inspect variables etc so you can discover why the error occured — JonasH, Mar 23 '20 at 15:01
@LarsTech I wanted to convert the string to a List of chars, which then are translated to dots and dashes for my output in the second TextBox. — Emanuel Avadani, Mar 23 '20 at 15:29
But you can't just convert a CharArray to a char. You can select the first index of the CharArray, if that's what you are trying to do. — LarsTech, Mar 23 '20 at 15:32
As the compiler warnings show, you only assign EingabeTextBox end never use that value. But here you are trying to convert a char-array (result of the .ToArray) to a single char. What do you expect from that line? Remove it and check the results — Hans Keﬆing, Mar 23 '20 at 15:35
OT instead of `Ausgabe.Append('\n')` you can also use `Ausgabe.AppendLine()`, which uses a "windows-style" end-of-line (or rather, an OS-specific EOL) — Hans Keﬆing, Mar 23 '20 at 15:37
@PaulF thanks for the tipp. I've done it and now I got a System.InvalidCastException. — Emanuel Avadani, Mar 23 '20 at 15:38
OT instead of catching an exception, use [ContainsKey()](https://learn.microsoft.com/en-us/dotnet/api/system.collections.generic.dictionary-2.containskey?view=netframework-4.8#System_Collections_Generic_Dictionary_2_ContainsKey__0_) to prevent it — Hans Keﬆing, Mar 23 '20 at 15:40
@HansKeﬆing I removed the line and changed to Ausgabe.AppendLine( ) and now it works. Thank you :-) — Emanuel Avadani, Mar 23 '20 at 15:43
@HansKeﬆing the exception was because of this line: ```EingabeTextBox = Convert.ToChar(_morseViewModel.MeinTextWert.ToLower().ToCharArray()); ``` I just deleted it and now it works... thank you very much :-) — Emanuel Avadani, Mar 24 '20 at 16:21

C# GUI keeps crashing due to System.InvalidCastException, when I press the button

0 Answers0