xenadmin/XenAdmin/Controls/Common/AutoHeightRadioButton.cs

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using System;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;

namespace XenAdmin.Controls.Common
{
    /// <summary>
    /// A RadioButton which automatically changes its height to accomodate its
    /// text when in AutoSize mode. This is useful as it enables a multi-line
    /// RadioButton to be put in a TableLayoutPanel. The table can then be made
    /// to vertically shrink/grow depending on the label text.
    /// Code based on http://blogs.msdn.com/b/jfoscoding/archive/2005/11/14/492554.aspx
    /// </summary>
    public class AutoHeightRadioButton : RadioButton
    {
        Size cachedSizeOfOneLineOfText = Size.Empty;
        Dictionary<Size, Size> preferredSizeHash = new Dictionary<Size, Size>();

        private void CacheTextSize()
        {
            preferredSizeHash.Clear();

            cachedSizeOfOneLineOfText = string.IsNullOrEmpty(Text)
                ? Size.Empty
                : TextRenderer.MeasureText(Text, Font, new Size(Int32.MaxValue, Int32.MaxValue), TextFormatFlags.WordBreak);
        }
        
        protected override void OnTextChanged(EventArgs e)
        {
            base.OnTextChanged(e);
            CacheTextSize();
            //this seems to be necessary in non-EN environments so it can resize correctly
            PerformLayout();
        }

        protected override void OnFontChanged(EventArgs e)
        {
            base.OnFontChanged(e);
            CacheTextSize();
            //this seems to be necessary in non-EN environments so it can resize correctly
            PerformLayout();
        }

        public override Size GetPreferredSize(Size proposedSize)
        {
            Size prefSize = base.GetPreferredSize(proposedSize);

            if (prefSize.Width > proposedSize.Width &&
                !string.IsNullOrEmpty(Text) &&
                (!proposedSize.Width.Equals(Int32.MaxValue) || !proposedSize.Height.Equals(Int32.MaxValue)))
            {
                Size bordersAndPadding = prefSize - cachedSizeOfOneLineOfText;
                Size newConstraints = proposedSize - bordersAndPadding;

                if (preferredSizeHash.ContainsKey(newConstraints))
                {
                    prefSize = preferredSizeHash[newConstraints];
                }
                else
                {
                    prefSize = bordersAndPadding + TextRenderer.MeasureText(Text, Font, newConstraints, TextFormatFlags.WordBreak);
                    preferredSizeHash[newConstraints] = prefSize;
                }
            }
            return prefSize;
        }
    }
}