diff --git a/Pilz.UI.Telerik/Extensions/RadFlyoutBaseExtensions.cs b/Pilz.UI.Telerik/Extensions/RadFlyoutBaseExtensions.cs
new file mode 100644
index 0000000..1fdb34d
--- /dev/null
+++ b/Pilz.UI.Telerik/Extensions/RadFlyoutBaseExtensions.cs
@@ -0,0 +1,12 @@
+using Pilz.UI.Telerik.Dialogs;
+using System.Diagnostics.CodeAnalysis;
+
+namespace Pilz.UI.Telerik.Extensions;
+
+public static class RadFlyoutBaseExtensions
+{
+    public static bool IsValid([NotNullWhen(true)] this RadFlyoutBase @this)
+    {
+        return @this != null && @this.Result == DialogResult.OK;
+    }
+}
diff --git a/Pilz.UI/Extensions/DialogResultExtensions.cs b/Pilz.UI/Extensions/DialogResultExtensions.cs
index f754b47..975f95f 100644
--- a/Pilz.UI/Extensions/DialogResultExtensions.cs
+++ b/Pilz.UI/Extensions/DialogResultExtensions.cs
@@ -1,31 +1,54 @@
-using System.Diagnostics.CodeAnalysis;
-
-namespace Pilz.UI.Extensions;
+namespace Pilz.UI.Extensions;
 
 public static class DialogResultExtensions
 {
-    public static bool Is([NotNullWhen(true)] this DialogResult? @this, DialogResult result)
+    public static bool Is(this DialogResult @this, DialogResult result)
     {
         return @this == result;
     }
-    
-    public static bool Is([NotNullWhen(true)] this DialogResult? @this, params DialogResult[] results)
+
+    public static bool IsNot(this DialogResult @this, DialogResult result)
+    {
+        return @this != result;
+    }
+
+    public static bool Is(this DialogResult @this, params DialogResult[] results)
     {
         return results.Any(result => @this == result);
     }
 
-    public static bool IsOk([NotNullWhen(true)] this DialogResult? @this)
+    public static bool IsNot(this DialogResult @this, params DialogResult[] results)
+    {
+        return results.All(result => @this != result);
+    }
+
+    public static bool IsOk(this DialogResult @this)
     {
         return @this == DialogResult.OK;
     }
 
-    public static bool IsYes([NotNullWhen(true)] this DialogResult? @this)
+    public static bool IsNotOk(this DialogResult @this)
+    {
+        return @this != DialogResult.OK;
+    }
+
+    public static bool IsYes(this DialogResult @this)
     {
         return @this == DialogResult.Yes;
     }
-    
-    public static bool IsCancel([NotNullWhen(true)] this DialogResult? @this)
+
+    public static bool IsNotYes(this DialogResult @this)
+    {
+        return @this != DialogResult.Yes;
+    }
+
+    public static bool IsCancel(this DialogResult @this)
     {
         return @this == DialogResult.Cancel;
     }
+
+    public static bool IsNotCancel(this DialogResult @this)
+    {
+        return @this != DialogResult.Cancel;
+    }
 }
diff --git a/Pilz.UI/Extensions/FlyoutBaseExtensions.cs b/Pilz.UI/Extensions/FlyoutBaseExtensions.cs
new file mode 100644
index 0000000..05eb2fa
--- /dev/null
+++ b/Pilz.UI/Extensions/FlyoutBaseExtensions.cs
@@ -0,0 +1,12 @@
+using Pilz.UI.Dialogs;
+using System.Diagnostics.CodeAnalysis;
+
+namespace Pilz.UI.Extensions;
+
+public static class FlyoutBaseExtensions
+{
+    public static bool IsValid([NotNullWhen(true)] this FlyoutBase @this)
+    {
+        return @this != null && @this.Result == DialogResult.OK;
+    }
+}