DevExpress GridView长文本行高优化：默认显部分内容+全文查看方案

作为常年和DevExpress WinForms打交道的开发者，针对你的需求，给你整理了几个落地性强的方案，都是项目里实测好用的：

方案1：鼠标悬停显示Tooltip（最简实现） #

这个方案零额外UI，用户体验友好，适合快速落地：

• 开启Memo编辑项的Tooltip：repositoryItemMemoEdit.ShowToolTips = true
• 自定义Tooltip内容：如果默认Tooltip只显示截断文本，你可以通过GridView.CustomDrawCell事件，把完整文本赋值给e.ToolTip：

  Private Sub GridView1_CustomDrawCell(sender As Object, e As DevExpress.XtraGrid.Views.Base.RowCellCustomDrawEventArgs) Handles GridView1.CustomDrawCell
      If e.Column.FieldName = "你的描述列名" Then
          Dim fullText As String = e.CellValue.ToString()
          ' 判断文本是否超过2行（根据字体和列宽计算高度）
          Dim textHeight As Integer = TextRenderer.MeasureText(fullText, repositoryItemMemoEdit.Font, New Size(e.Bounds.Width, 0), TextFormatFlags.WordBreak).Height
          Dim lineHeight As Integer = repositoryItemMemoEdit.Font.Height
          If textHeight > lineHeight * 2 Then
              e.ToolTip = fullText
          End If
      End If
  End Sub
  

• 进阶优化：用TooltipController统一管理Tooltip样式，比如设置自动弹出延迟、背景色等。

方案2：展开/收起按钮（交互性最强） #

适合需要用户主动控制显示的场景，步骤如下：

1. 设置默认行高：先计算2行文本的高度，固定默认行高：

   Dim defaultRowHeight As Integer = repositoryItemMemoEdit.Font.Height * 2 + 8 ' 加8是上下边距
   GridView1.RowHeight = defaultRowHeight
   GridView1.OptionsView.RowAutoHeight = False
   

2. 绘制展开/收起按钮：在GridView.CustomDrawCell事件中，给超过2行的单元格绘制一个小图标（比如+/-）：

   Private Sub GridView1_CustomDrawCell(sender As Object, e As DevExpress.XtraGrid.Views.Base.RowCellCustomDrawEventArgs) Handles GridView1.CustomDrawCell
       If e.Column.FieldName = "你的描述列名" Then
           Dim fullText As String = e.CellValue.ToString()
           Dim textHeight As Integer = TextRenderer.MeasureText(fullText, repositoryItemMemoEdit.Font, New Size(e.Bounds.Width, 0), TextFormatFlags.WordBreak).Height
           Dim lineHeight As Integer = repositoryItemMemoEdit.Font.Height
           If textHeight > lineHeight * 2 Then
               ' 绘制展开/收起图标（可使用DevExpress自带的ImageCollection）
               Dim iconBounds As New Rectangle(e.Bounds.Right - 16, e.Bounds.Top + 2, 12, 12)
               If GridView1.GetRowHeight(e.RowHandle) = defaultRowHeight Then
                   e.Graphics.DrawImage(My.Resources.ExpandIcon, iconBounds)
               Else
                   e.Graphics.DrawImage(My.Resources.CollapseIcon, iconBounds)
               End If
               ' 截断文本，避免覆盖图标
               Dim truncatedText As String = TextRenderer.MeasureText(fullText, repositoryItemMemoEdit.Font, New Size(e.Bounds.Width - 20, 0), TextFormatFlags.WordBreak Or TextFormatFlags.EndEllipsis).ToString()
               e.DisplayText = truncatedText
           End If
       End If
   End Sub
   

3. 处理点击事件：在GridView.MouseDown事件中，判断点击的是图标区域，切换行高：

   Private Sub GridView1_MouseDown(sender As Object, e As MouseEventArgs) Handles GridView1.MouseDown
       Dim hitInfo As GridHitInfo = GridView1.CalcHitInfo(e.Location)
       If hitInfo.InRowCell AndAlso hitInfo.Column.FieldName = "你的描述列名" Then
           Dim fullText As String = GridView1.GetRowCellValue(hitInfo.RowHandle, hitInfo.Column).ToString()
           Dim textHeight As Integer = TextRenderer.MeasureText(fullText, repositoryItemMemoEdit.Font, New Size(hitInfo.Column.Width, 0), TextFormatFlags.WordBreak).Height
           Dim lineHeight As Integer = repositoryItemMemoEdit.Font.Height
           If textHeight > lineHeight * 2 Then
               Dim iconBounds As New Rectangle(hitInfo.Bounds.Right - 16, hitInfo.Bounds.Top + 2, 12, 12)
               If iconBounds.Contains(e.Location) Then
                   If GridView1.GetRowHeight(hitInfo.RowHandle) = defaultRowHeight Then
                       ' 展开：自动计算行高
                       GridView1.SetRowHeight(hitInfo.RowHandle, textHeight + 8)
                   Else
                       ' 收起：恢复默认行高
                       GridView1.SetRowHeight(hitInfo.RowHandle, defaultRowHeight)
                   End If
               End If
           End If
       End If
   End Sub
   

方案3：超链接弹窗（独立查看体验） #

适合需要大面积查看编辑文本的场景，实现思路：

1. 绘制超链接样式文本：在CustomDrawCell事件中，把超过2行的文本截断，加上“...查看全文”，并设置为蓝色下划线样式：

   Private Sub GridView1_CustomDrawCell(sender As Object, e As DevExpress.XtraGrid.Views.Base.RowCellCustomDrawEventArgs) Handles GridView1.CustomDrawCell
       If e.Column.FieldName = "你的描述列名" Then
           Dim fullText As String = e.CellValue.ToString()
           Dim textHeight As Integer = TextRenderer.MeasureText(fullText, repositoryItemMemoEdit.Font, New Size(e.Bounds.Width, 0), TextFormatFlags.WordBreak).Height
           Dim lineHeight As Integer = repositoryItemMemoEdit.Font.Height
           If textHeight > lineHeight * 2 Then
               e.DisplayText = $"{TextRenderer.MeasureText(fullText, repositoryItemMemoEdit.Font, New Size(e.Bounds.Width, 0), TextFormatFlags.WordBreak Or TextFormatFlags.EndEllipsis)}...查看全文"
               ' 设置绘制样式为超链接
               e.Appearance.ForeColor = Color.Blue
               e.Appearance.Options.UseForeColor = True
               e.Appearance.TextOptions.HAlignment = DevExpress.Utils.HorzAlignment.Near
           End If
       End If
   End Sub
   

2. 弹出窗口显示全文：在GridView.RowCellClick事件中，判断点击的是超链接文本，弹出一个带MemoEdit的窗口：

   Private Sub GridView1_RowCellClick(sender As Object, e As DevExpress.XtraGrid.Views.Grid.RowCellClickEventArgs) Handles GridView1.RowCellClick
       If e.Column.FieldName = "你的描述列名" Then
           Dim fullText As String = GridView1.GetRowCellValue(e.RowHandle, e.Column).ToString()
           Dim textHeight As Integer = TextRenderer.MeasureText(fullText, repositoryItemMemoEdit.Font, New Size(e.Column.Width, 0), TextFormatFlags.WordBreak).Height
           Dim lineHeight As Integer = repositoryItemMemoEdit.Font.Height
           If textHeight > lineHeight * 2 Then
               ' 新建弹窗Form，里面放一个MemoEdit
               Dim detailForm As New Form()
               detailForm.Text = "详细描述"
               detailForm.Size = New Size(600, 400)
               Dim memoEdit As New DevExpress.XtraEditors.MemoEdit()
               memoEdit.Dock = DockStyle.Fill
               memoEdit.Text = fullText
               memoEdit.Properties.ReadOnly = True
               detailForm.Controls.Add(memoEdit)
               detailForm.ShowDialog()
           End If
       End If
   End Sub
   

额外优化建议 #

• 性能优化：如果数据量较大，建议提前在DataTable中添加一个隐藏列，存储文本的行数或计算后的高度，避免每次绘制都重复计算TextRenderer.MeasureText
• 统一样式：用DevExpress的Appearances机制统一设置Tooltip、弹窗的样式，保持和主应用一致
• 编辑支持：如果需要编辑全文，可以在弹窗的MemoEdit中开启编辑模式，编辑完成后同步回GridView的数据源

内容的提问来源于stack exchange，提问作者J.L