1、RichTextBox扩展类

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;
using System.Windows.Documents;
using System.Windows.Media;namespace PrintTime
{/// <summary>/// RichTextBox长度自动增长 扩展类/// </summary>public static class FlowDocumentExtensions{private static IEnumerable<TextElement> GetRunsAndParagraphs(FlowDocument doc){for (TextPointer position = doc.ContentStart;position != null && position.CompareTo(doc.ContentEnd) <= 0;position = position.GetNextContextPosition(LogicalDirection.Forward)){if (position.GetPointerContext(LogicalDirection.Forward) == TextPointerContext.ElementEnd){Run run = position.Parent as Run;if (run != null){yield return run;}else{Paragraph para = position.Parent as Paragraph;if (para != null){yield return para;}}}}}public static FormattedText GetFormattedText(this FlowDocument doc){if (doc == null){throw new ArgumentNullException("doc");}//doc.PagePadding = new System.Windows.Thickness(0, 0, 0, 0);//设置文本的边距FormattedText output = new FormattedText(GetText(doc),CultureInfo.CurrentCulture,doc.FlowDirection,new Typeface(doc.FontFamily, doc.FontStyle, doc.FontWeight, doc.FontStretch),doc.FontSize,doc.Foreground);int offset = 0;foreach (TextElement el in GetRunsAndParagraphs(doc)){Run run = el as Run;if (run != null){int count = run.Text.Length;output.SetFontFamily(run.FontFamily, offset, count);output.SetFontStyle(run.FontStyle, offset, count);output.SetFontWeight(run.FontWeight, offset, count);output.SetFontSize(run.FontSize, offset, count);output.SetForegroundBrush(run.Foreground, offset, count);output.SetFontStretch(run.FontStretch, offset, count);output.SetTextDecorations(run.TextDecorations, offset, count);offset += count;}else{offset += Environment.NewLine.Length;}}return output;}private static string GetText(FlowDocument doc){StringBuilder sb = new StringBuilder();foreach (TextElement el in GetRunsAndParagraphs(doc)){Run run = el as Run;sb.Append(run == null ? Environment.NewLine : run.Text);}return sb.ToString();}}}

2、RichTextBox控件定义

RichTextBox rtb = new RichTextBox(){Margin = new Thickness(5),AllowDrop = true,HorizontalAlignment = HorizontalAlignment.Left,BorderThickness = new Thickness(1),VerticalAlignment = VerticalAlignment.Top,BorderBrush = Brushes.Transparent,FontSize = model.FontSize,//FontFamily = new FontFamily(cb_FontFamily.SelectedValue.ToString()),FontFamily = new FontFamily(model.FontName),Background = Brushes.Transparent,};string strName = "rtb_" + dateName;if (textTpe.Equals("timeStamp")){Thread.Sleep(1);dateName = DateTime.Now.ToString("yyyyMMddHHmmss");strName = "rtb_date_" + dateName + "_" + model.TimestampSelectIndex;rtb.IsReadOnly = true;gridWords.Tag = model.TimestampText== null ?  "": model.TimestampText;rtb.Tag = model.TimestampFormat == null ? "" : model.TimestampFormat;}rtb.Name = strName;rtb.Document = new FlowDocument() { LineHeight = 1 };//修改行间距//rtb.TextChanged += new TextChangedEventHandler((o, q) => rtb.Width = rtb.Document.GetFormattedText().WidthIncludingTrailingWhitespace + 16);rtb.VerticalScrollBarVisibility = ScrollBarVisibility.Disabled;rtb.PreviewMouseLeftButtonDown += Rtb_PreviewMouseLeftButtonDown;rtb.PreviewMouseRightButtonDown += Rtb_PreviewMouseRightButtonDown;rtb.Loaded += Rtb_Loaded;rtb.GotFocus += Rtb_GotFocus;rtb.LostFocus += Rtb_LostFocus;rtb.TextChanged += Rtb_TextChanged;rtb.ContextMenu = (ContextMenu)this.FindResource("ContextMenu");gridWords.Children.Add(rtb);

3、事件处理

        private string rtbLastText = "";private void Rtb_TextChanged(object sender, TextChangedEventArgs e){RichTextBox richTextBox = sender as RichTextBox;if (richTextBox != null){DockPanel dockPanel = richTextBox.Parent as DockPanel;if (dockPanel != null){if (dockPanel.Width != double.NaN){dockPanel.Width = double.NaN;}if (dockPanel.Height != double.NaN){dockPanel.Height = double.NaN;}}if (System.Environment.OSVersion.Version.Major == 6 && System.Environment.OSVersion.Version.Minor == 1)//win7模板加粗文本最后一字换行问题
                {richTextBox.Width = richTextBox.Document.GetFormattedText().WidthIncludingTrailingWhitespace + 18;}else{richTextBox.Width = richTextBox.Document.GetFormattedText().WidthIncludingTrailingWhitespace + 16;}richTextBox.Document.LineHeight = 1;//处理复制粘贴后行高变为Nan问题//richTextBox.Document.PagePadding = new Thickness(0);TextRange a = new TextRange(richTextBox.Document.ContentStart, richTextBox.Document.ContentEnd);if (rtbLastText != a.Text.ToString() && !isUndo){rtbLastText = a.Text.ToString();CommandStack.AddUndo(richTextBox, CommandTypes.RichTextBoxEdit, new object[] { });}}}