disable Locate button when filename is invalid

Author: christso

GitContentSearch.UI/Converters/FileNameValidationConverter.cs

@@ -0,0 +1,26 @@
+using Avalonia.Data.Converters;
+using System;
+using System.Globalization;
+using System.Linq;
+
+namespace GitContentSearch.UI.Converters
+{
+    public class FileNameValidationConverter : IValueConverter
+    {
+        private static readonly char[] InvalidCharacters = { '\\', '/', ':', '*', '?', '"', '<', '>', '|' };
+
+        public object? Convert(object? value, Type targetType, object? parameter, CultureInfo culture)
+        {
+            if (value is string fileName)
+            {
+                return !fileName.Any(c => InvalidCharacters.Contains(c));
+            }
+            return true;
+        }
+
+        public object? ConvertBack(object? value, Type targetType, object? parameter, CultureInfo culture)
+        {
+            throw new NotImplementedException();
+        }
+    }
+} 

GitContentSearch.UI/Views/MainWindow.axaml

@@ -17,6 +17,7 @@
         <converters:OperationColorConverter x:Key="OperationColorConverter"/>
         <converters:BoolConverter x:Key="BoolConverter"/>
         <converters:OperationButtonTextConverter x:Key="OperationButtonTextConverter"/>
+        <converters:FileNameValidationConverter x:Key="FileNameValidationConverter"/>
     </Window.Resources>
 
     <Design.DataContext>
@@ -35,8 +36,14 @@
                     Classes="Locate"
                     Content="Locate" 
                     Command="{Binding LocateFileCommand}" 
-                    IsEnabled="{Binding !IsSearching}"
-                    Margin="8,0"/>
+                    Margin="8,0">
+                <Button.IsEnabled>
+                    <MultiBinding Converter="{x:Static BoolConverters.And}">
+                        <Binding Path="!IsSearching"/>
+                        <Binding Path="FilePath" Converter="{StaticResource FileNameValidationConverter}"/>
+                    </MultiBinding>
+                </Button.IsEnabled>
+            </Button>
             <Button Grid.Column="3" 
                     Classes="Secondary"
                     Content="Browse"