C# 如何停止CheckBoxRenderer.DrawCheckBox创建的文本分层

我有以下单元格，用于数据网格上的自定义列数据类型

public class DataGridViewReviewerCell : DataGridViewCell
{
    protected override object GetFormattedValue(object value, int rowIndex, ref DataGridViewCellStyle cellStyle,
                                                TypeConverter valueTypeConverter,
                                                TypeConverter formattedValueTypeConverter,
                                                DataGridViewDataErrorContexts context)
    {
        return Value;
    }

    protected override void Paint(Graphics graphics, Rectangle clipBounds, Rectangle cellBounds, int rowIndex,
                                  DataGridViewElementStates cellState, object value, object formattedValue,
                                  string errorText, DataGridViewCellStyle cellStyle,
                                  DataGridViewAdvancedBorderStyle advancedBorderStyle,
                                  DataGridViewPaintParts paintParts)
    {
        base.Paint(graphics, clipBounds, cellBounds, rowIndex, cellState, "", "", errorText,
                 cellStyle, advancedBorderStyle, paintParts);
        var parent = (DataGridViewReviewerColumn) OwningColumn;
        var columnValue = (ReviewerCheckBox) Value;

        CheckBoxRenderer.DrawCheckBox(
            graphics,
            new Point(cellBounds.X + 4, cellBounds.Y + 4),
            new Rectangle(cellBounds.X + 2, cellBounds.Y + 4, cellBounds.Width, cellBounds.Height - (4 * 2)),
            "     " + columnValue.ReviewerEmployeeName,
            parent.InheritedStyle.Font, 
            TextFormatFlags.Left,
            false,
            (columnValue.IsChecked ? CheckBoxState.CheckedNormal : CheckBoxState.UncheckedNormal));

    }
}

该类按预期工作，但是每次调用Paint（）时，文本（当前为

“”+columnValue.ReviewerEmployeeName

）都会不断分层，从而创建非常不可读的文本。我似乎找不到任何能解决这个问题的方法

慢代码 下面是一段运行非常缓慢的代码。当我将其置于调试模式时，它似乎在无休止地运行

using System.ComponentModel;
using System.Drawing;
using System.Windows.Forms;
using System.Windows.Forms.VisualStyles;
using System;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();

            dataGridView1.Rows.Add("STEP A", new ReviewerCheckBox());
            dataGridView1.Rows.Add("STEP B", new ReviewerCheckBox());
        }

        private void dataGridView1_CellClick(object sender, DataGridViewCellEventArgs e)
        {
            if (e.RowIndex == -1 || e.ColumnIndex != 1) return;

            var cell = (ReviewerCheckBox) dataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex].Value;
            cell.IsChecked = !cell.IsChecked;
            cell.ReviewerEmployeeName = (cell.IsChecked ? Environment.UserName : String.Empty);

            //MessageBox.Show("Testing");
        }
    }

    public class ReviewerCheckBox
    {
        public string ReviewerEmployeeName { get; set; }
        public bool IsChecked { get; set; }
        public bool IsRequired { get; set; }
    }
}

    public class DataGridViewReviewerColumn : DataGridViewColumn
    {
        public DataGridViewReviewerColumn()
        {
            CellTemplate = new DataGridViewReviewerCell();
            ReadOnly = false;
            SortMode = DataGridViewColumnSortMode.NotSortable;
            Resizable = DataGridViewTriState.False;
        }
    }

---

您应该检查

paintParts

参数以确定应该绘制哪些零件。例如，如果背景需要绘制，将设置DataGridViewPaintParts.Backgound标志

if (paintParts.HasFlag(DataGridViewPaintParts.Background))
{
  using (SolidBrush cellBackground =
    new SolidBrush(cellStyle.BackColor))
  {
    graphics.FillRectangle(cellBackground, cellBounds);
  }    
}

if (paintParts.HasFlag(DataGridViewPaintParts.Border))
{
  PaintBorder(graphics, clipBounds, cellBounds, cellStyle,
    advancedBorderStyle);
}

// Paint you cell content here

下面是一个更完整的示例

using System;
using System.Windows.Forms;
using System.Drawing;
using System.Windows.Forms.VisualStyles;

namespace HideMainWinForm
{
  class DataGridViewReviewerCell : DataGridViewCell
  {
    protected override object GetFormattedValue(object value, int rowIndex, ref DataGridViewCellStyle cellStyle, System.ComponentModel.TypeConverter valueTypeConverter, System.ComponentModel.TypeConverter formattedValueTypeConverter, DataGridViewDataErrorContexts context)
    {
      return value;
    }

    protected override void Paint(System.Drawing.Graphics graphics, System.Drawing.Rectangle clipBounds, System.Drawing.Rectangle cellBounds, int rowIndex, DataGridViewElementStates cellState, object value, object formattedValue, string errorText, DataGridViewCellStyle cellStyle, DataGridViewAdvancedBorderStyle advancedBorderStyle, DataGridViewPaintParts paintParts)
    {
      if (paintParts.HasFlag(DataGridViewPaintParts.Background))
      {
        using (SolidBrush cellBackground =
          new SolidBrush(cellStyle.BackColor))
        {
          graphics.FillRectangle(cellBackground, cellBounds);
        }
      }

      if (paintParts.HasFlag(DataGridViewPaintParts.Border))
      {
        PaintBorder(graphics, clipBounds, cellBounds, cellStyle,
          advancedBorderStyle);
      }

      if (value != null)
      {
        CheckBoxRenderer.DrawCheckBox(
          graphics,
          new Point(cellBounds.X + 4, cellBounds.Y + 4),
          new Rectangle(cellBounds.X+24,cellBounds.Y+4, cellBounds.Width-24, cellBounds.Height-4),
          formattedValue.ToString(),
          OwningColumn.InheritedStyle.Font,
          TextFormatFlags.Left,
          false,
          CheckBoxState.CheckedNormal);
      }
    }
  }
}

两个

HasFlag

函数调用可以转换为

if ((paintParts & DataGridViewPaintParts.Background) == 
    DataGridViewPaintParts.Background)
{
  ...
}

if ((paintParts & DataGridViewPaintParts.Border) == 
    DataGridViewPaintParts.Border)
{
  ...
}

---

谢谢你的回复，克里斯。我的

paintParts

参数似乎为空。另外，

paintParts

没有

HasFlag

方法。@Mike，HasFlag是自framework 3.5以来

enum

的成员。paintParts不能为null，因为它是不可为null的值类型（枚举）。因为我使用的是VS2010，所以我切换到了4.0，错误消失了。我将找出如何将其更改为与3.5兼容。谢谢。：）@Mike，MSDN错误地将Enum记录为在Framework 3.5中具有HasFlag方法。我已经添加了备用标志检查，您可以在Framework 4.0之前的框架版本中使用它。关于为什么使用此确切代码会导致

Paint（）

在无限循环中被调用，您有什么想法吗？