Add BoolToStringConverter

Elwig/Controls/BoolToValueConverter.cs

@@ -0,0 +1,19 @@
+using System;
+using System.Windows.Data;
+
+namespace Elwig.Controls {
+    public class BoolToValueConverter<T> : IValueConverter {
+        public T FalseValue { get; set; }
+        public T TrueValue { get; set; }
+
+        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) {
+            return (bool)value ? TrueValue : FalseValue;
+        }
+
+        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) {
+            return value?.Equals(TrueValue) ?? false;
+        }
+    }
+
+    public class BoolToStringConverter : BoolToValueConverter<string> { }
+}