Add userdata fields to all control hierarchy.

Dashboard/Controls/UIBase.cs

@@ -1,5 +1,6 @@
 
 using System;
+using System.Collections.Generic;
 using Dashboard.ImmediateDraw;
 using OpenTK.Mathematics;
 
@@ -8,7 +9,7 @@ namespace Dashboard.Controls
     /// <summary>
     /// Bases for all UI elements.
     /// </summary>
-    public abstract class UIBase
+    public abstract class UIBase : IDbUserdata
     {
         private Vector2 size;
 
@@ -59,6 +60,8 @@ namespace Dashboard.Controls
         public bool IsMaximumSizeSet => MaximumSize != new Vector2(-1, -1);
         public bool IsMinimumSizeSet => MinimumSize != new Vector2(-1, -1);
 
+        public Dictionary<string, object> Userdata { get; } = new Dictionary<string, object>();
+
         public virtual void NotifyEvent(object? sender, EventArgs args)
         {
         }
@@ -87,6 +90,29 @@ namespace Dashboard.Controls
         {
             Resized?.Invoke(sender, ea);
         }
+
+        public bool IsDisposed { get; private set; } = false;
+
+        protected virtual void Dispose(bool disposing)
+        {
+            foreach (object userdata in Userdata.Values)
+            {
+                if (userdata is IDisposable disposable)
+                    disposable.Dispose();
+            }
+        }
+
+        protected void DisposeInvoker(bool disposing)
+        {
+            if (IsDisposed)
+                return;
+
+            IsDisposed = true;
+
+            Dispose(disposing);
+        }
+
+        public void Dispose() => DisposeInvoker(true);
     }
 
     public class ResizedEventArgs : EventArgs

Dashboard/IDbUserdata.cs

@@ -0,0 +1,21 @@
+
+using System;
+using System.Collections.Generic;
+
+namespace Dashboard
+{
+    /// <summary>
+    /// Common interface for Dashboard objects that accept userdata.
+    /// </summary>
+    /// <remarks>
+    /// Dashboard will call dispose on any and all objects which implement IDisposable.
+    /// If this is an issue, please guard your object against this using a wrapper.
+    /// </remarks
+    public interface IDbUserdata : IDisposable
+    {
+        /// <summary>
+        /// Userdata dictionary.
+        /// </summary>
+        public Dictionary<string, object> Userdata { get; }
+    }
+}