xamlparseexception was unhandled what i can do

Question

when i run my app i have this exception

Cannot create instance of 'MainWindow' defined in assembly 'MediaTransferTester, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'. Exception has been thrown by the target of an invocation.  Error in markup file 'MainWindow.xaml' Line 1 Position 9.

this is my xaml code

<Window x:Class="MediaTransferTester.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow"
        Width="878"
        Height="588">
    <Grid Width="853" Height="525">
        <GroupBox Name="groupBox1"
                  Width="504"
                  Margin="12,12,0,316"
                  HorizontalAlignment="Left"
                  Header="EndPoint Config">

            <Grid Width="468" Height="139">
                <Label Name="label1"
                       Width="108"
                       Height="28"
                       Margin="6,12,0,0"
                       HorizontalAlignment="Left"
                       VerticalAlignment="Top"
                       Content="Loal IPs" />
                <Label Name="label2"
                       Width="108"
                       Height="28"
                       Margin="6,46,0,0"
                       HorizontalAlignment="Left"
                       VerticalAlignment="Top"
                       Content="Remote IP" />
                <Label Name="label3"
                       Width="58"
                       Margin="183,12,0,116"
                       HorizontalAlignment="Left"
                       Content="RTP Port" />
                <Label Name="label4"
                       Width="58"
                       Height="28"
                       Margin="183,47,0,0"
                       HorizontalAlignment="Left"
                       VerticalAlignment="Top"
                       Content="RTP Port" />
                <Label Name="label5"
                       Height="28"
                       Margin="6,84,0,0"
                       HorizontalAlignment="Left"
                       VerticalAlignment="Top"
                       Content="TransportType" />
                <RadioButton Name="rbUDP"
                             Height="16"
                             Margin="112,89,0,0"
                             HorizontalAlignment="Left"
                             VerticalAlignment="Top"
                             Content="UDP"
                             GroupName="TransportType"
                             IsChecked="True" />
                <RadioButton Name="rbMSTP"
                             Height="16"
                             Margin="165,89,0,0"
                             HorizontalAlignment="Left"
                             VerticalAlignment="Top"
                             Content="MSTP"
                             GroupName="TransportType" />
                <RadioButton Name="rbTCPConnect"
                             Height="16"
                             Margin="226,89,0,0"
                             HorizontalAlignment="Left"
                             VerticalAlignment="Top"
                             Content="TCP Connect"
                             GroupName="TransportType" />
                <RadioButton Name="rbTcpListen"
                             Width="76"
                             Height="16"
                             Margin="317,89,0,0"
                             HorizontalAlignment="Left"
                             VerticalAlignment="Top"
                             Content="TCP Listen"
                             GroupName="TransportType" />
                <ListBox Name="listBoxEndPointAddress"
                         Width="102"
                         Height="37"
                         Margin="75,11,0,0"
                         HorizontalAlignment="Left"
                         VerticalAlignment="Top"
                         ScrollViewer.HorizontalScrollBarVisibility="Auto"
                         ScrollViewer.VerticalScrollBarVisibility="Visible" />
                <TextBox Name="TBRemoteEndpointIP"
                         Width="102"
                         Height="23"
                         Margin="75,52,0,0"
                         HorizontalAlignment="Left"
                         VerticalAlignment="Top"
                         LostFocus="TBRemoteEndpointIP_LostFocus" />
                <TextBox Name="LocalrtpPort"
                         Width="38"
                         Height="23"
                         Margin="247,12,0,0"
                         HorizontalAlignment="Left"
                         VerticalAlignment="Top"
                         LostFocus="LocalrtpPort_LostFocus"
                         MaxLength="4" />
                <TextBox Name="RemotertpPort"
                         Width="38"
                         Height="23"
                         Margin="247,46,0,0"
                         HorizontalAlignment="Left"
                         VerticalAlignment="Top"
                         LostFocus="RemotertpPort_LostFocus"
                         MaxLength="4" />
                <TextBox Name="localTcpPort"
                         Width="37"
                         Height="23"
                         Margin="0,12,75,0"
                         HorizontalAlignment="Right"
                         VerticalAlignment="Top"
                         LostFocus="localTcpPort_LostFocus"
                         MaxLength="4" />
                <TextBox Name="RemoteTcpPort"
                         Width="37"
                         Height="23"
                         Margin="356,46,0,0"
                         HorizontalAlignment="Left"
                         VerticalAlignment="Top"
                         LostFocus="RemoteTcpPort_LostFocus"
                         MaxLength="4" />
                <Label Name="label9"
                       Width="57"
                       Margin="291,11,0,117"
                       HorizontalAlignment="Left"
                       Content="TCP Port" />
                <Label Name="label11"
                       Width="57"
                       Height="28"
                       Margin="291,49,0,0"
                       HorizontalAlignment="Left"
                       VerticalAlignment="Top"
                       Content="TCP Port" />
            </Grid>

        </GroupBox>
        <GroupBox Name="groupBox2"
                  Width="504"
                  Height="269"
                  Margin="12,215,0,0"
                  HorizontalAlignment="Left"
                  VerticalAlignment="Top"
                  Header="AudioConfig">
            <Grid Width="486"
                  Height="245"
                  HorizontalAlignment="Stretch"
                  VerticalAlignment="Stretch">
                <Label Name="label6"
                       Width="90"
                       Height="28"
                       Margin="15,30,0,0"
                       HorizontalAlignment="Left"
                       VerticalAlignment="Top"
                       Content="Source Devices" />
                <Label Name="label7"
                       Width="108"
                       Height="28"
                       Margin="15,89,0,0"
                       HorizontalAlignment="Left"
                       VerticalAlignment="Top"
                       Content="Sink Devices" />
                <Label Name="label10"
                       Height="28"
                       Margin="15,150,0,0"
                       HorizontalAlignment="Left"
                       VerticalAlignment="Top"
                       Content="Send Audio Codecs" />
                <ListBox Name="SourceDeviceList"
                         Width="229"
                         Height="52"
                         Margin="150,6,0,0"
                         HorizontalAlignment="Left"
                         VerticalAlignment="Top"
                         ScrollViewer.HorizontalScrollBarVisibility="Auto"
                         ScrollViewer.VerticalScrollBarVisibility="Visible" />
                <ListBox Name="SinkDeviceList"
                         Width="229"
                         Height="53"
                         Margin="150,64,0,0"
                         HorizontalAlignment="Left"
                         VerticalAlignment="Top"
                         ScrollViewer.HorizontalScrollBarVisibility="Auto"
                         ScrollViewer.VerticalScrollBarVisibility="Visible" />
                <Label Name="label8"
                       Width="122"
                       Height="28"
                       Margin="15,211,0,0"
                       HorizontalAlignment="Left"
                       VerticalAlignment="Top"
                       Content="Receive Audio Codecs" />
                <ListBox Name="SendCodecsNamelistBox"
                         Width="229"
                         Height="55"
                         Margin="150,123,0,0"
                         HorizontalAlignment="Left"
                         VerticalAlignment="Top"
                         ScrollViewer.HorizontalScrollBarVisibility="Auto"
                         ScrollViewer.VerticalScrollBarVisibility="Visible" />
                <ListBox Name="ReceiveCodecsNamelistBox"
                         Width="229"
                         Height="56"
                         Margin="150,183,0,0"
                         HorizontalAlignment="Left"
                         VerticalAlignment="Top"
                         ScrollViewer.HorizontalScrollBarVisibility="Auto"
                         ScrollViewer.VerticalScrollBarVisibility="Visible" />
            </Grid>
        </GroupBox>

        <Button Name="btnStartSend"
                Width="75"
                Height="23"
                Margin="12,490,0,0"
                HorizontalAlignment="Left"
                VerticalAlignment="Top"
                Click="btnStartSend_Click"
                Content="Start Send" />
        <Button Name="btnSaveConfig"
                Width="109"
                Height="23"
                Margin="195,490,0,0"
                HorizontalAlignment="Left"
                VerticalAlignment="Top"
                Click="btnSaveConfig_Click"
                Content="Save Configration" />
        <TextBox Name="StatTextBox"
                 Width="319"
                 Height="461"
                 Margin="522,23,0,0"
                 HorizontalAlignment="Left"
                 VerticalAlignment="Top"
                 Background="Black"
                 FontFamily="Consolas"
                 FontSize="9"
                 Foreground="White"
                 IsEnabled="True"
                 IsReadOnly="True"
                 ScrollViewer.HorizontalScrollBarVisibility="Auto"
                 ScrollViewer.VerticalScrollBarVisibility="Auto" />
        <Button Name="btnStartReceve"
                Width="75"
                Height="23"
                Margin="93,490,0,0"
                HorizontalAlignment="Left"
                VerticalAlignment="Top"
                Click="btnStartReceve_Click"
                Content="Start Receve" />
    </Grid>
</Window>

and this is the exception details

System.Windows.Markup.XamlParseException was unhandled Message=Cannot create instance of 'MainWindow' defined in assembly 'MediaTransferTester, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'. Exception has been thrown by the target of an invocation. Error in markup file 'MainWindow.xaml' Line 1 Position 9. Source=PresentationFramework LineNumber=1 LinePosition=9 StackTrace: at System.Windows.Markup.XamlParseException.ThrowException(String message, Exception innerException, Int32 lineNumber, Int32 linePosition, Uri baseUri, XamlObjectIds currentXamlObjectIds, XamlObjectIds contextXamlObjectIds, Type objectType) at System.Windows.Markup.XamlParseException.ThrowException(ParserContext parserContext, Int32 lineNumber, Int32 linePosition, String message, Exception innerException) at System.Windows.Markup.BamlRecordReader.ThrowExceptionWithLine(String message, Exception innerException) at System.Windows.Markup.BamlRecordReader.CreateInstanceFromType(Type type, Int16 typeId, Boolean throwOnFail) at System.Windows.Markup.BamlRecordReader.GetElementAndFlags(BamlElementStartRecord bamlElementStartRecord, Object& element, ReaderFlags& flags, Type& delayCreatedType, Int16& delayCreatedTypeId) at System.Windows.Markup.BamlRecordReader.BaseReadElementStartRecord(BamlElementStartRecord bamlElementRecord) at System.Windows.Markup.BamlRecordReader.ReadElementStartRecord(BamlElementStartRecord bamlElementRecord) at System.Windows.Markup.BamlRecordReader.ReadRecord(BamlRecord bamlRecord) at System.Windows.Markup.BamlRecordReader.Read(Boolean singleRecord) at System.Windows.Markup.TreeBuilderBamlTranslator.ParseFragment() at System.Windows.Markup.TreeBuilder.Parse() at System.Windows.Markup.XamlReader.LoadBaml(Stream stream, ParserContext parserContext, Object parent, Boolean closeStream) at System.Windows.Application.LoadBamlStreamWithSyncInfo(Stream stream, ParserContext pc) at System.Windows.Application.LoadComponent(Uri resourceLocator, Boolean bSkipJournaledProperties) at System.Windows.Application.DoStartup() at System.Windows.Application.<.ctor>b__0(Object unused) at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Boolean isSingleParameter) at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler) at System.Windows.Threading.Dispatcher.WrappedInvoke(Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler) at System.Windows.Threading.DispatcherOperation.InvokeImpl() at System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(Object state) at System.Threading.ExecutionContext.runTryCode(Object userData) at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData) at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Windows.Threading.DispatcherOperation.Invoke() at System.Windows.Threading.Dispatcher.ProcessQueue() at System.Windows.Threading.Dispatcher.WndProcHook(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled) at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled) at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o) at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Boolean isSingleParameter) at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler) at System.Windows.Threading.Dispatcher.WrappedInvoke(Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler) at System.Windows.Threading.Dispatcher.InvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Boolean isSingleParameter) at System.Windows.Threading.Dispatcher.Invoke(DispatcherPriority priority, Delegate method, Object arg) at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam) at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg) at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame) at System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame) at System.Windows.Threading.Dispatcher.Run() at System.Windows.Application.RunDispatcher(Object ignore) at System.Windows.Application.RunInternal(Window window) at System.Windows.Application.Run(Window window) at System.Windows.Application.Run() at MediaTransferTester.App.Main() in C:\Users\t.said\documents\visual studio 2010\Projects\MediaTransferTester\MediaTransferTester\obj\x86\Debug\App.g.cs:line 0 at System.AppDomain._nExecuteAssembly(Assembly 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) at System.Threading.ThreadHelper.ThreadStart() InnerException: System.Reflection.TargetInvocationException Message=Exception has been thrown by the target of an invocation. Source=mscorlib StackTrace: at System.RuntimeTypeHandle.CreateInstance(RuntimeType type, Boolean publicOnly, Boolean noCheck, Boolean& canBeCached, RuntimeMethodHandle& ctor, Boolean& bNeedSecurityCheck) at System.RuntimeType.CreateInstanceSlow(Boolean publicOnly, Boolean fillCache) at System.RuntimeType.CreateInstanceImpl(Boolean publicOnly, Boolean skipVisibilityChecks, Boolean fillCache) at System.Activator.CreateInstance(Type type, Boolean nonPublic) at System.Windows.Markup.BamlRecordReader.CreateInstanceFromType(Type type, Int16 typeId, Boolean throwOnFail) InnerException: System.NullReferenceException Message=Object reference not set to an instance of an object. Source=MediaTransferTester StackTrace: at MediaTransferTester.MainWindow.RegisterHandlers() in C:\Users\t.said\documents\visual studio 2010\Projects\MediaTransferTester\MediaTransferTester\MainWindow.xaml.cs:line 48 at MediaTransferTester.MainWindow..ctor() in C:\Users\t.said\documents\visual studio 2010\Projects\MediaTransferTester\MediaTransferTester\MainWindow.xaml.cs:line 39 InnerException:

Answer 1

look at the bottom of your inner exception:

InnerException: System.NullReferenceException Message=Object reference not set to an instance of an object. Source=MediaTransferTester StackTrace: at MediaTransferTester.MainWindow.RegisterHandlers() in C:\Users\t.said\documents\visual studio 2010\Projects\MediaTransferTester\MediaTransferTester\MainWindow.xaml.cs:line 48 at MediaTransferTester.MainWindow..ctor() in C:\Users\t.said\documents\visual studio 2010\Projects\MediaTransferTester\MediaTransferTester\MainWindow.xaml.cs:line 39 InnerException: 

Right there, it looks like your problem is a null reference in your code-behind. MainWindow.xaml.cs line 48. Include your code-behind for that section if you need more help than that.