Merge pull request #2915 from Krypton-Suite/V105-LTS-2910-bug-kryptoncombobox-override-font-property-causes-form-designer-error

* `KryptonComboBox` override Font property causes form designer error…

Author: PWagner1

Documents/Changelog/Changelog.md

@@ -2,6 +2,12 @@
 
 ====
 
+## 2026-04-20 - Build 2604 (Version 105-LTS - Patch 2) - April 2026
+
+* Resolved [#2910](https://github.com/Krypton-Suite/Standard-Toolkit/issues/2910), `KryptonComboBox` override Font property causes form designer error
+
+====
+
 # 2026-01-19 - Build 2501 (Version 105-LTS - Patch 1) - January 2026
 
 * Resolved/Implemented [#1651](https://github.com/Krypton-Suite/Standard-Toolkit/issues/1651), KComboBox's should follow the DateTimePicker layout(s)

Source/Krypton Components/Krypton.Toolkit/Controls Toolkit/KryptonComboBox.cs

@@ -1461,9 +1461,15 @@ public override Color BackColor
     [AllowNull]
     public override Font Font
     {
-        get => base.Font;
+        get => GetStateCommonFont() ?? base.Font;
 
-        set => base.Font = value!;
+        set
+        {
+            // Always set base.Font to ensure consistency
+            base.Font = value!;
+            // Also try to set StateCommon font, but don't fail if it's not available
+            SetStateCommonFont(value);
+        }
     }
 
     /// <summary>
@@ -2435,6 +2441,54 @@ protected virtual void OnHoverSelectionChanged(HoveredSelectionChangedEventArgs
     /// </summary>
     /// <param name="e"></param>
     protected virtual void OnToolTipNeeded(ToolTipNeededEventArgs e) => ToolTipNeeded?.Invoke(this, e);
+
+    /// <summary>
+    /// Gets the font from StateCommon.ComboBox.Content.Font safely, handling design mode serialization issues.
+    /// </summary>
+    /// <returns>The font from StateCommon, or null if not available or during problematic design time access.</returns>
+    protected virtual Font? GetStateCommonFont()
+    {
+        try
+        {
+            // Use null-conditional operators to safely access nested properties
+            // This prevents issues during design time serialization when StateCommon might not be fully initialized
+            return StateCommon.ComboBox.Content?.Font;
+        }
+        catch
+        {
+            // If StateCommon is not fully initialized or there's a serialization issue,
+            // return null to fall back to base.Font
+            return null;
+        }
+    }
+
+    /// <summary>
+    /// Sets the font to StateCommon.ComboBox.Content.Font safely, handling design mode serialization issues.
+    /// </summary>
+    /// <param name="value">The font value to set.</param>
+    /// <returns>True if the font was set to StateCommon, false to fall back to base.Font.</returns>
+    protected virtual bool SetStateCommonFont(Font? value)
+    {
+        try
+        {
+            // Use null-conditional operators to safely access nested properties
+            // This prevents issues during design time serialization when StateCommon might not be fully initialized
+            if (StateCommon.ComboBox?.Content != null)
+            {
+                StateCommon.ComboBox.Content.Font = value;
+
+                return true;
+            }
+        }
+        catch
+        {
+            // If StateCommon is not fully initialized or there's a serialization issue,
+            // return false to fall back to base.Font
+        }
+
+        return false;
+    }
+
     // ReSharper restore VirtualMemberNeverOverridden.Global
     #endregion