可设置行距的Label

  最近在做Winform的项目，发现Winform和WebForm里相同名称的控件还是真是有区别。比如Label,它的大小Size有两种模式，自动大小(只有一行，宽度根据内容调整)，还有一种是自定义宽和高。自定义的内容不同的话，宽和高还真能调节，调整不正确的话，可能有的内容就不能显示。还有就是换行的行距也不能设置，一切都是默认值，如果是B/S模式就太简单了。

  网上找了下个例子(百度就可以找到).以下是那位仁兄的：

 ////////////////////////////////////////////////////// /// ///功能：可以改变文本行距（行间距）的Label ///作者：emanlee ///用于：c# 2003,2005 ///时间：2006-8-10 /// ///////////////////////////////////////////////////// using System; using System.ComponentModel; using System.Collections.Generic; using System.Diagnostics; using System.Text; using System.Drawing; namespace compass.Common { public partial class myLabel : System.Windows.Forms.Label { int lineDistance = 5;//行间距 public int LineDistance { get { return lineDistance; } set { lineDistance = value; } } public myLabel() { InitializeComponent(); //这行有问题 } public myLabel(IContainer container) { container.Add(this); InitializeComponent(); //这行有问题 } protected override void OnPaint(System.Windows.Forms.PaintEventArgs e) { Graphics g = e.Graphics; String drawString = this.Text; Font drawFont = this.Font; SolidBrush drawBrush = new SolidBrush(this.ForeColor); SizeF textSize = g.MeasureString(this.Text, this.Font);//文本的矩形区域大小 int lineCount = Convert.ToInt16(textSize.Width / this.Width) + 1;//计算行数 this.Height = Convert.ToInt16((textSize.Height + lineDistance) * lineCount);//计算调整后的高度 this.AutoSize = false; float x = 0.0F; float y = 0.0F; StringFormat drawFormat = new StringFormat(); int step = 1; lineCount = drawString.Length;//行数不超过总字符数目 for (int i = 0; i < lineCount; i++) { //计算每行容纳的字符数目 int charCount; for (charCount = 0; charCount < drawString.Length; charCount++) { string subN = drawString.Substring(0, charCount); string subN1 = drawString.Substring(0, charCount + 1); if (g.MeasureString(subN, this.Font).Width <= this.Width && g.MeasureString(subN1, this.Font).Width > this.Width) { step = charCount; break; } } string subStr; if (charCount == drawString.Length)//最后一行文本 { subStr = drawString; e.Graphics.DrawString(subStr, drawFont, drawBrush, x, Convert.ToInt16(textSize.Height * i) + i * LineDistance, drawFormat); break; } else { subStr = drawString.Substring(0, step);//当前行文本 drawString = drawString.Substring(step);//剩余文本 e.Graphics.DrawString(subStr, drawFont, drawBrush, x, Convert.ToInt16(textSize.Height * i) + i * LineDistance, drawFormat); } } } } }
 

 发现上面的控件存在两个问题：

   1、控件的最终高度是窗体Paint的时候计算出来。控件运行时前期的高度会保持控件设计时的高度。只Paint以后高度才会重新计算。

   2、效率。在计算行字数时这里应用的循环算法效率不高。而且外循环是drawstring.Length,即文本的数量。虽然这里会提前结束循环。但内循环仍然效率不高。

   以下是我针对上述问题做的改进。如下代码：

////////////////////////////////////////////////////// /// ///功能：可以改变文本行距（行间距）的Label ///作者：Tomas Yang///用于：c# 2003,2005,2008///时间：2011-01-06/// ///////////////////////////////////////////////////// using System;using System.ComponentModel;using System.Collections.Generic;using System.Diagnostics;using System.Text;using System.Drawing;namespace Tom.Component{ 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(object sender, EventArgs e) { Changed(this.Font, this.Width, this.Text); } public LabelTx(IContainer container) { container.Add(this); //base.Height //InitializeComponent(); } public int FHeight { get { return this.Font.Height; } } protected int Height { get { return height; } set { height = value; base.Height = value; } } public override string Text { get { return base.Text; } set { //is.Font.Size. base.Text = value; Changed(this.Font, this.Width, value); } } protected void Changed(Font ft, int iWidth, string value) { iHeight = 0; if (value != "") { if (gcs == null) { gcs = this.CreateGraphics(); SizeF sf0 = gcs.MeasureString(new string('测', 20), ft); searchPos = (int)(iWidth * 20 / sf0.Width); } nrLine = value.Split(new string[1] { "/r/n" }, StringSplitOptions.RemoveEmptyEntries); section = nrLine.Length; nrLinePos = new string[section]; SizeF sf1, sf2; string temps, tempt; string drawstring; int temPos, ipos; for (int i = 0; i < section; i++) { ipos = 0; temPos = searchPos; if (searchPos >= nrLine[i].Length) { ipos+=nrLine[i].Length; nrLinePos[i] += "," + ipos.ToString(); iHeight++; continue; } drawstring = nrLine[i]; nrLinePos[i] = ""; while (drawstring.Length > searchPos) { bool isfind = false; for (int j = searchPos; j < drawstring.Length; j++) { temps = drawstring.Substring(0, j); tempt = drawstring.Substring(0, j + 1); sf1 = gcs.MeasureString(temps, ft); sf2 = gcs.MeasureString(tempt, ft); if (sf1.Width < iWidth && sf2.Width > iWidth) { iHeight++; ipos += j; nrLinePos[i] += "," + ipos.ToString(); isfind = true; drawstring = drawstring.Substring(j); break; } } if (!isfind) { //drawstring = drawstring.Substring(searchPos); //iHeight++; break; } } ipos += drawstring.Length; nrLinePos[i] += "," + ipos.ToString(); iHeight++; //tempLine = (int)(sf1.Width - 1) / this.Width + 1; //iHeight += tempLine; } } this.Height = iHeight * (ft.Height + lineDistance); } protected override void OnPaint(System.Windows.Forms.PaintEventArgs e) { //base.OnPaint(e); //if (isPaint) return; //isPaint = true; Graphics g = e.Graphics; String drawString = this.Text; Font drawFont = this.Font; SolidBrush drawBrush = new SolidBrush(this.ForeColor); SizeF textSize = g.MeasureString(this.Text, this.Font);//文本的矩形区域大小 int lineCount = Convert.ToInt16(textSize.Width / this.Width) + 1;//计算行数 int fHeight = this.Font.Height; int htHeight = 0; this.AutoSize = false; float x = 0.0F; float y = 0.0F; StringFormat drawFormat = new StringFormat(); int step = 1; bool isFirst = true; SizeF sf1, sf2; string subN, subN1; lineCount = drawString.Length;//行数不超过总字符数目 int i, idx, first; string subStr, tmpStr="", midStr = ""; string[] idxs; for (i = 0; i < section; i++) { first = 0; subStr = nrLine[i]; if (nrLinePos[i]!=null) tmpStr = nrLinePos[i].TrimStart(','); midStr = subStr.Substring(first); if (tmpStr != "") { idxs = tmpStr.Split(','); for (int j = 0; j < idxs.Length; j++) { idx = int.Parse(idxs[j]); midStr = subStr.Substring(first, idx - first); e.Graphics.DrawString(midStr, drawFont, drawBrush, x, Convert.ToInt16(htHeight), drawFormat); htHeight += (fHeight + lineDistance); first = idx; } //midStr = subStr.Substring(first); } //e.Graphics.DrawString(midStr, drawFont, drawBrush, x, Convert.ToInt16(htHeight), drawFormat); //htHeight += ( lineDistance);//fHeight + } } }}
 当然这里改动下，设置段落高度。有兴趣可以改下。