Anzeige der Info, dass man in einer Read-Only Konversation nichts senden kann.

ChatController/ChatController.csproj

@@ -68,6 +68,7 @@
     </Compile>
     <Compile Include="Converter\BoolToVisibilityConverter.cs" />
     <Compile Include="Converter\BroadcastCheckBoxVisibilityMultiConverter.cs" />
+    <Compile Include="Converter\ChatBoxInfoVisibilityConverter.cs" />
     <Compile Include="Converter\OwnChatNullVisibilityConverter.cs" />
     <Compile Include="Converter\StringEmptyToVisibilityConverter.cs" />
     <Compile Include="Converter\StringToBoolConverter.cs" />

ChatController/ChatMainControl.xaml

@@ -17,6 +17,7 @@
         <converter:StringEmptyToVisibilityConverter x:Key="StringEmptyToVisibilityConverter" />
         <converter:UserProfilePictureVisibilityConverter x:Key="UserProfilePictureVisibilityConverter" />
         <converter:BroadcastCheckBoxVisibilityMultiConverter x:Key="BroadcastCheckBoxVisibilityMultiConverter" />
+        <converter:ChatBoxInfoVisibilityConverter x:Key="ChatBoxVisibilityConverter" />
         
         <SolidColorBrush x:Key="DarkBackColor" Color="#A9B8C2" />
         <SolidColorBrush x:Key="LightBackColor" Color="#F3F3F3" />
@@ -626,6 +627,12 @@
                         </Button>
                     </Grid>
                     <!-- #endregion Nachrichtentextbox -->
+
+                    <!-- #region Infotext, wenn Zurückschreiben nicht möglich -->
+                    <Grid Grid.Row="2" Visibility="{Binding Path=CurrentContact, UpdateSourceTrigger=PropertyChanged, Converter={StaticResource ChatBoxVisibilityConverter}}">
+                        <TextBlock Margin="10" FontSize="15" HorizontalAlignment="Center" Text="In dieser Gruppe dürfen Sie leider nicht senden." />
+                    </Grid>
+                    <!-- #endregion -->
                 </Grid>
             </Grid>
         </Border>

ChatController/Converter/BoolToVisibilityConverter.cs

@@ -14,6 +14,11 @@ namespace ChatController.Converter
                 return parameter is string reverseString && Equals(reverseString, "reverse") ? boolValue ? Visibility.Visible : Visibility.Collapsed : boolValue ? Visibility.Collapsed : Visibility.Visible;
             }
 
+            if(value is null)
+            {
+                return Visibility.Collapsed;
+            }
+
             return Visibility.Visible;
         }
 

ChatController/Converter/ChatBoxInfoVisibilityConverter.cs

@@ -0,0 +1,26 @@
+using System;
+using System.Globalization;
+using System.Windows;
+using System.Windows.Data;
+using ChatController.ChatKlassen;
+
+namespace ChatController.Converter
+{
+    public class ChatBoxInfoVisibilityConverter : IValueConverter
+    {
+        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            if(value is Contact contact)
+            {
+                return contact.IsChatMessageInputGridVisible ? Visibility.Collapsed : Visibility.Visible;
+            }
+
+            return Visibility.Collapsed;
+        }
+
+        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            throw new NotImplementedException();
+        }
+    }
+}