C# winform自定义Label控件使其能设置行距

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Drawing;
using System.ComponentModel;
namespace WindowsFormsApplication10
{
    public partial class LabelTx : System.Windows.Forms.Label
    {
        int lineDistance = 5;//行间距
        Graphics gcs;
        int iHeight = 0, height = 200;
        string[] nrLine;
        string[] nrLinePos;
        int searchPos = 0;
        int section = 1;
        public int LineDistance
        {
            get { return lineDistance; }
            set
            {
                lineDistance = value;
                Changed(this.Font, this.Width, this.Text);
            }
        }
        public LabelTx()
            : base()
        {
            //this.TextChanged += new EventHandler(LabelTx_TextChanged);
            this.SizeChanged += new EventHandler(LabelTx_SizeChanged);
            this.FontChanged += new EventHandler(LabelTx_FontChanged);
            //this.Font = new Font(this.Font.FontFamily, this.Font.Size, GraphicsUnit.Pixel);
        }
        void LabelTx_FontChanged(object sender, EventArgs e)
        {
            Changed(this.Font, this.Width, this.Text);
        }
        void LabelTx_SizeChanged(