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
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/// <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
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/// <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：
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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
