Added classes to represent a toolbar button. This is a base class tha…

…t can be extended. The alternative to a button is a separator hence the separation.

src/BetterControls/BetterToolbar/Items/BetterToolbarButton.NativeStructure.cs

@@ -0,0 +1,58 @@
+using System.Runtime.InteropServices;
+
+namespace BetterControls
+{
+    /// <summary>
+    /// Extend this class to create a toolbar item that is a button.
+    /// </summary>
+    partial class BetterToolbarButton
+    {
+        /// <summary>
+        /// <inheritdoc/>
+        /// </summary>
+        /// <returns><inheritdoc/></returns>
+        internal override NativeMethods.TBBUTTON ComputeTbButton()
+        {
+            NativeMethods.TBBUTTON structure = base.ComputeTbButton();
+
+            structure.fsStyle |= NativeMethods.BTNS_AUTOSIZE;
+
+            if (ShowImage)
+                structure.iBitmap = ImageIndexer.ComputedIndex;
+            if (Enabled)
+                structure.fsState |= NativeMethods.TBSTATE_ENABLED;
+            if (Pressed)
+                structure.fsState |= NativeMethods.TBSTATE_PRESSED;
+
+            structure.iString = _stringIndex = OwnerToolbar.AddString(Text);
+
+            return structure;
+        }
+
+        /// <summary>
+        /// <inheritdoc/>
+        /// </summary>
+        /// <returns><inheritdoc/></returns>
+        internal override NativeMethods.TBBUTTONINFO ComputeTbButtonInfo()
+        {
+            NativeMethods.TBBUTTONINFO structure = base.ComputeTbButtonInfo();
+
+            structure.dwMask |= NativeMethods.TBIF_IMAGE | NativeMethods.TBIF_STATE | NativeMethods.TBIF_STYLE;
+
+            if (ShowImage)
+                structure.iImage = ImageIndexer.ComputedIndex;
+            if (Enabled)
+                structure.fsState |= NativeMethods.TBSTATE_ENABLED;
+            if (Pressed)
+                structure.fsState |= NativeMethods.TBSTATE_PRESSED;
+
+            structure.dwMask |= NativeMethods.TBIF_TEXT;
+
+            structure.pszText = Marshal.StringToHGlobalAuto(Text);
+
+            _previousText = Text;
+
+            return structure;
+        }
+    }
+}