DataGridView带图标的单元格实现代码

目的：

扩展 c# winform 自带的表格控件，使其可以自动判断数据的上下界限值，并标识溢出。

这里使用的方法是：扩展 表格的列 对象：datagridviewcolumn。

1.创建类：decimalcheckcell

/// <summary>
/// 可进行范围检查的 数值单元格
/// </summary>
public class decimalcheckcell : datagridviewtextboxcell
{
private bool checkmaxvalue = false;
private bool checkminvalue = false;
private decimal maxvalue = 0;
private decimal minvalue = 0;

public decimal maxvalue
{
 get { return maxvalue; }
 internal set { maxvalue = value; }
}

public decimal minvalue
{
 get { return minvalue; }
 internal set { minvalue = value; }
}

public bool checkmaxvalue
{
 get { return checkmaxvalue; }
 internal set { checkmaxvalue = value; }
}

public bool checkminvalue
{
 get { return checkminvalue; }
 internal set
 {
 checkminvalue = value;
 }
}


public override object clone()
{
 decimalcheckcell c = base.clone() as decimalcheckcell;
 c.checkmaxvalue = this.checkmaxvalue;
 c.checkminvalue = this.checkminvalue;
 c.maxvalue = this.maxvalue;
 c.minvalue = this.minvalue;
 return c;
}

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)
{
 // paint the base content
 base.paint(graphics, clipbounds, cellbounds, rowindex, cellstate,
 value, formattedvalue, errortext, cellstyle,
 advancedborderstyle, paintparts);

 // 上下界限溢出判断
 if (this.rowindex < 0 || this.owningrow.isnewrow) // 行序号不为-1，且不是新记录行（貌似没用）
 return;
 if (value == null) return;

 decimal vcurvalue = convert.todecimal(value);
 bool overvalue = false;
 image img = null;
 if (checkmaxvalue)
 {
 overvalue = vcurvalue > maxvalue;
 img = vstest.properties.resources.undo; // 图片来自 添加的资源文件
 }
 if (checkminvalue && !overvalue)
 {
 overvalue = vcurvalue < minvalue;
 img = vstest.properties.resources.redo; // 图片来自 添加的资源文件
 }

 // 将图片绘制在 数值文本后面
 if (overvalue && img != null)
 {
 var vsize = graphics.measurestring(vcurvalue.tostring(), cellstyle.font);

 system.drawing.drawing2d.graphicscontainer container = graphics.begincontainer();
 graphics.setclip(cellbounds);
 graphics.drawimageunscaled(img, new point(cellbounds.location.x + (int)vsize.width, cellbounds.location.y));
 graphics.endcontainer(container);
 }
}

protected override bool setvalue(int rowindex, object value)
{
 if (rowindex >= 0)
 {
 try
 {
  decimal vdeci = convert.todecimal(value); // 筛选非数字
  base.errortext = string.empty;
 }
 catch (exception ex)
 {
  base.errortext = "输入错误" + ex.message;
  return false;
 }
 }
 return base.setvalue(rowindex, value);
}


}

2.创建类：decimalcheckcolumn

 

/// <summary>
/// 可进行范围检查的 数值列
/// </summary>
public class decimalcheckcolumn : datagridviewcolumn
{
 private bool checkmaxvalue = false;
 private bool checkminvalue = false;
 private decimal maxvalue = 0;
 private decimal minvalue = 0;

 public decimal maxvalue
 {
  get { return maxvalue; }
  set
  {
   maxvalue = value;
   (base.celltemplate as decimalcheckcell).maxvalue = value;
  }
 }

 public decimal minvalue
 {
  get { return minvalue; }
  set
  {
   minvalue = value;
   (base.celltemplate as decimalcheckcell).minvalue = value;
  }
 }

 /// <summary>
 /// 是否对值上界限进行检查，与maxvalue配合使用
 /// </summary>
 public bool checkmaxvalue
 {
  get { return checkmaxvalue; }
  set
  {
   checkmaxvalue = value;
   (base.celltemplate as decimalcheckcell).checkmaxvalue = value;
  }
 }
 /// <summary>
 /// 是否对值下界限进行检查，与minvalue配合使用
 /// </summary>
 public bool checkminvalue
 {
  get { return checkminvalue; }
  set
  {
   checkminvalue = value;
   (base.celltemplate as decimalcheckcell).checkminvalue = value;
  }
 }

 public decimalcheckcolumn()
  : base(new decimalcheckcell())
 {

 }

 public override object clone()
 {
  decimalcheckcolumn c = base.clone() as decimalcheckcolumn;
  c.checkmaxvalue = this.checkmaxvalue;
  c.checkminvalue = this.checkminvalue;
  c.maxvalue = this.maxvalue;
  c.minvalue = this.minvalue;

  return c;
 }

}

3.现在就可以使用了，在窗体上拖一个 datagridview 控件，添加如下代码：

private void testform_load(object sender, eventargs e)
 {
  initcontrolsproperties(); // 初始化

  // 绑定数据
  datatable dtabel = new datatable();
  dtabel.columns.add("id",typeof(int));
  dtabel.columns.add("testvalue",typeof(decimal));
  random rnd = new random();
  for (int i = 0; i < 10; i++) // 随机10个数
  {
   var vdr = dtabel.newrow();
   vdr[0] = i + 1;
   vdr[1] = rnd.next(50);
   dtabel.rows.add(vdr);
  }
  this.datagridview1.datasource = dtabel;
 }

 private void initcontrolsproperties()
 {
  decimalcheckcolumn columnroleid = new decimalcheckcolumn();
  columnroleid.datapropertyname = "id";
  columnroleid.defaultcellstyle.alignment = datagridviewcontentalignment.middleleft;
  columnroleid.name = "id";
  columnroleid.headertext = "序号";
  columnroleid.width = 50;
  this.datagridview1.columns.add(columnroleid);

  decimalcheckcolumn columnrolename = new decimalcheckcolumn();
  columnrolename.datapropertyname = "testvalue";
  columnrolename.defaultcellstyle.alignment = datagridviewcontentalignment.middleleft;
  columnrolename.name = "testvalue";
  columnrolename.headertext = "测试数据";
  columnrolename.width = 100;

  columnrolename.checkmaxvalue = true; // 进行最大值检查
  columnrolename.maxvalue = 41;
  columnrolename.checkminvalue = true; // 进行最小值检查
  columnrolename.minvalue = 7;

  this.datagridview1.columns.add(columnrolename);

  //this.datagridview1.allowusertoaddrows = false;
  //this.datagridview1.allowusertodeleterows = false;
  //this.datagridview1.readonly = true;
  this.datagridview1.autogeneratecolumns = false;

 }

运行效果如下图左所示

 那右边图是什么鬼？

现在还有一个问题没有解决：默认第一次加载出来的数据，并不能完全判断出是否超界限，有时会有一两个能判断，有时完全不能判断，但只需要用鼠标去点击各单元格，它又可以自动识别。暂时没有发现问题原因所在。

 以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。

原文链接：http://www.cnblogs.com/CUIT-DX037/archive/2017/08/13/7354057.html