目录
本文介绍了一个自定义DataGridView进度条单元格的实现方案。通过继承DataGridViewImageCell并重写Paint方法，实现了在单元格中绘制进度条的效果。关键点包括：1)使用progressBrush绘制进度条；2)处理进度值转换确保0-100范围；3)解决Int32到Image的强制转换错误。同时定义了DataGridViewProgressColumn列类型和TestProgressData数据结构，并提供了数据绑定示例。该方案适用于需要显示进度状态的WinForms应用，解决了默认DataGridView无法直接显示进度条的问题。
1 重绘类
public class DataGridViewProgressCell : DataGridViewImageCell
{
// 用于绘制进度条的刷子
private static readonly Brush progressBrush = new SolidBrush(Color.LightSeaGreen);
private static readonly Brush textBrush = new SolidBrush(Color.Black);
private static readonly Pen borderPen = new Pen(Color.DarkGray);
public DataGridViewProgressCell()
{
// 设置单元格的值类型为int
ValueType = typeof(int);
}
// 重写单元格的类型
public override Type ValueType
{
get { return typeof(int); }
set { base.ValueType = typeof(int); }
}
// 提供默认值
public override object DefaultNewRowValue
{
get { return 0; }
}
// 关键修复：重写此方法避免类型转换错误
protected override object GetFormattedValue(object value,
int rowIndex,
ref DataGridViewCellStyle cellStyle,
TypeConverter valueTypeConverter,
TypeConverter formattedValueTypeConverter,
DataGridViewDataErrorContexts context)
{
// 直接返回空，避免将int强制转为Image
return null;
}
// 重绘单元格，绘制进度条
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)
{
// 基础背景绘制
base.Paint(graphics, clipBounds, cellBounds, rowIndex, cellState,
value, null, errorText, cellStyle, advancedBorderStyle,
paintParts & ~DataGridViewPaintParts.ContentForeground);
int progress = 0;
// 尝试将值转换为进度值(0-100)
if (value != null && int.TryParse(value.ToString(), out int val))
{
progress = Math.Max(0, Math.Min(100, val)); // 确保值在0-100之间
}
// 绘制单元格背景
using (Brush backBrush = new SolidBrush(cellStyle.BackColor))
{
graphics.FillRectangle(backBrush, cellBounds);
}
// 绘制进度条背景
Rectangle progressRect = new Rectangle(
cellBounds.X + 2,
cellBounds.Y + 2,
cellBounds.Width - 4,
cellBounds.Height - 4);
graphics.FillRectangle(Brushes.White, progressRect);
// 绘制进度条
int progressWidth = (int)((progressRect.Width * progress) / 100.0);
Rectangle fillRect = new Rectangle(
progressRect.X,
progressRect.Y,
progressWidth,
progressRect.Height);
graphics.FillRectangle(progressBrush, fillRect);
// 绘制进度条边框
graphics.DrawRectangle(borderPen, progressRect);
// 绘制进度文本
string text = $"{progress}%";
SizeF textSize = graphics.MeasureString(text, cellStyle.Font);
graphics.DrawString(text, cellStyle.Font, textBrush,
cellBounds.X + (cellBounds.Width - textSize.Width) / 2,
cellBounds.Y + (cellBounds.Height - textSize.Height) / 2);
}
}
// 自定义进度条列
public class DataGridViewProgressColumn : DataGridViewColumn
{
public DataGridViewProgressColumn()
{
CellTemplate = new DataGridViewProgressCell();
this.ValueType = typeof(int);
// 关键修复：禁用默认图像生成
this.DefaultCellStyle.NullValue = null;
DefaultCellStyle.Alignment = DataGridViewContentAlignment.MiddleCenter;
}
}
// 定义数据结构体
public class TestProgressData
{
public string devIDInfo { get; set; }
public int progressValue { get; set; } // 进度值(0-100)
public string progressStatus { get; set; } // 实时进度状态
public string testResult { get; set; } // 测试结果
public string errorMessage { get; set; } // 错误信息
}2 添加数据
private void InitializeDeviceInfoGrid(int group)
{
//dataGridView_data.DataError += dataGridView_DataError;
// 设置DataGridView属性
//dataGridView_data.Dock = DockStyle.Fill;
dataGridView_data.AllowUserToAddRows = false;
dataGridView_data.ReadOnly = true;
dataGridView_data.RowHeadersVisible = false;
// 添加状态列
dataGridView_data.Columns.Add(new DataGridViewTextBoxColumn
{
HeaderText = "设备名",
DataPropertyName = "devIDInfo",
Width = 150
});
// 添加进度条列
DataGridViewProgressColumn progressColumn = new DataGridViewProgressColumn();
progressColumn.HeaderText = "进度";
progressColumn.Width = 200;
progressColumn.DataPropertyName = "progressValue";
dataGridView_data.Columns.Add(progressColumn);
// 添加状态列
dataGridView_data.Columns.Add(new DataGridViewTextBoxColumn
{
HeaderText = "实时进度状态",
DataPropertyName = "progressStatus",
Width = 150
});
// 添加测试结果列
dataGridView_data.Columns.Add(new DataGridViewTextBoxColumn
{
HeaderText = "测试结果",
DataPropertyName = "testResult",
Width = 120
});
// 添加错误信息列
dataGridView_data.Columns.Add(new DataGridViewTextBoxColumn
{
HeaderText = "错误信息",
DataPropertyName = "errorMessage",
Width = 200
});
AddTestData();
// 绑定数据
//dataGridView_data.DataSource = dataList;
}
// 添加测试数据
private void AddTestData()
{
// 添加几行测试数据
dataList.Add(new TestProgressData
{
devIDInfo = "123",
progressValue = 30,
progressStatus = "正在处理",
testResult = "",
errorMessage = ""
}); ;
dataList.Add(new TestProgressData
{
devIDInfo = "123",
progressValue = 100,
progressStatus = "处理完成",
testResult = "成功",
errorMessage = ""
});
dataList.Add(new TestProgressData
{
devIDInfo = "123",
progressValue = 50,
progressStatus = "正在验证",
testResult = "",
errorMessage = ""
});
dataList.Add(new TestProgressData
{
devIDInfo = "123",
progressValue = 75,
progressStatus = "正在传输",
testResult = "",
errorMessage = "网络延迟"
});
dataList.Add(new TestProgressData
{
devIDInfo = "123",
progressValue = 100,
progressStatus = "处理完成",
testResult = "失败",
errorMessage = "文件格式错误"
});
// 刷新数据绑定
dataGridView_data.DataSource = null;
dataGridView_data.DataSource = dataList;
//dataGridView_data.Refresh();
}3 遇到的问题
DataGridView错误：从“System.Int32”到“System.Drawing.Image”的强制转换无效。，行：0，列：1