扩展GridView（五）——固定表头、指定行或指定列

GridView既强大又好用。为了让它更强大、更好用，我们来写一个继承自GridView的控件。
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https://files.cnblogs.com/webabcd/yycontrols.rar

扩展GridView（五）——固定表头、指定行或指定列

介绍
平时使用GridView的时候会有固定表头、指定行或指定列的需求，就像Excel冻结行、列那样。其实我们可以用CSS来搞定。扩展一下GridView，通过设置几个属性来达到这样的功能。

控件开发
1、新建一个继承自GridView的类。

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/// <summary>
/// 继承自GridView
/// </summary>
[ToolboxData(@"<{0}:SmartGridView runat='server'></{0}:SmartGridView>")]
public class SmartGridView : GridView
{
}

2、新建一个FixRowCol类，有五个属性

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using System;
using System.Collections.Generic;
using System.Text;
using System.ComponentModel;
namespace YYControls.SmartGridView
{
/// <summary>
    /// 固定表头、指定行或指定列的属性类
    /// </summary>
    [TypeConverter(typeof(ExpandableObjectConverter))]
public class FixRowCol
{
private bool _isFixHeader;
/// <summary>
        /// 固定表头否？
        /// </summary>
        [Description("固定表头否？"), Category("扩展"), DefaultValue(false), NotifyParentProperty(true)]
public virtual bool IsFixHeader
{
get { return _isFixHeader; }
set { _isFixHeader = value; }
}
private string _fixRowIndices;
/// <summary>
        /// 需要固定的行的索引（用逗号“,”分隔）
        /// </summary>
        [Description("需要固定的行的索引（用逗号“,”分隔）"), Category("扩展"), NotifyParentProperty(true)]
public virtual string FixRowIndices
{
get { return _fixRowIndices; }
set { _fixRowIndices = value; }
}
private string _fixColumnIndices;
/// <summary>
        /// 需要固定的列的索引（用逗号“,”分隔）
        /// </summary>
        [Description("需要固定的列的索引（用逗号“,”分隔）"), Category("扩展"), NotifyParentProperty(true)]
public virtual string FixColumnIndices
{
get { return _fixColumnIndices; }
set { _fixColumnIndices = value; }
}
private System.Web.UI.WebControls.Unit _tableWidth;
/// <summary>
        /// 表格的宽度
        /// </summary>
        [Description("表格的宽度"), Category("扩展"), NotifyParentProperty(true)]
public System.Web.UI.WebControls.Unit TableWidth
{
get { return _tableWidth; }
set { _tableWidth = value; }
}
private System.Web.UI.WebControls.Unit _tableHeight;
/// <summary>
        /// 表格的高度
        /// </summary>
        [Description("表格的高度"), Category("扩展"), NotifyParentProperty(true)]
public System.Web.UI.WebControls.Unit TableHeight
{
get { return _tableHeight; }
set { _tableHeight = value; }
}
/// <summary>
        /// ToString();
        /// </summary>
        /// <returns></returns>
        public override string ToString()
{
return "FixRowCol";
}
}
}

3、在继承自GridView的类中加一个复杂对象属性，该复杂对象就是第2步创建的那个FixRowCol

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private FixRowCol _fixRowCol;
/// <summary>
/// 固定表头、指定行或指定列
/// </summary>
[
Description("固定表头、指定行或指定列"),
Category("扩展"),
DefaultValue(""),
DesignerSerializationVisibility(DesignerSerializationVisibility.Content),
PersistenceMode(PersistenceMode.InnerProperty)
]
public virtual FixRowCol FixRowCol
{
get
{
if (_fixRowCol == null)
{
_fixRowCol = new FixRowCol();
}
return _fixRowCol;
}
}

4、在继承自GridView的那个类的构造函数内加一个RowDataBound事件的处理，在该事件内设置每个单元格的样式，以实现固定表头、指定行或指定列的功能。

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/// <summary>
/// 构造函数
/// </summary>
public SmartGridView()
: base()
{
// 新增“SmartGridView_RowDataBound”事件处理
    this.RowDataBound += new GridViewRowEventHandler(SmartGridView_RowDataBound);
}
/// <summary>
/// RowDataBound事件
/// </summary>
/// <param name="sender">sender</param>
/// <param name="e">e</param>
protected void SmartGridView_RowDataBound(object sender, GridViewRowEventArgs e)
{
SmartGridView sgv = (SmartGridView) sender;
if (e.Row.RowType == DataControlRowType.DataRow || e.Row.RowType == DataControlRowType.Header)
{
// 给每一个指定固定的列的单元格加上css属性
        if (!String.IsNullOrEmpty(FixRowCol.FixColumnIndices))
{
// 列索引
            foreach (string s in FixRowCol.FixColumnIndices.Split(','))
{
int i;
if (!Int32.TryParse(s, out i))
throw new ArgumentException("FixColumnIndices", "含有非整形的字符");
if (i > e.Row.Cells.Count)
throw new ArgumentOutOfRangeException("FixColumnIndices", "溢出");
e.Row.Cells[i].Attributes.Add("style", "position: relative; left: expression(this.offsetParent.scrollLeft);");
}
}
bool isFixRow = false; // 当前行是否固定
        if (FixRowCol.IsFixHeader && e.Row.RowType == DataControlRowType.Header)
{
isFixRow = true;
}
if (!String.IsNullOrEmpty(FixRowCol.FixRowIndices) && e.Row.RowType == DataControlRowType.DataRow)
{
// 行索引
            foreach (string s in FixRowCol.FixRowIndices.Split(','))
{
int i;
if (!Int32.TryParse(s, out i))
throw new ArgumentException("FixRowIndices", "含有非整形的字符");
if (i > e.Row.Cells.Count)
throw new ArgumentOutOfRangeException("FixRowIndices", "溢出");
if (i == e.Row.RowIndex)
{
isFixRow = true;
break;
}
}
}
// 固定该行
        if (isFixRow)
{
// 该行的每一个单元格
            for (int j = 0; j < e.Row.Cells.Count; j++)
{
// 该单元格不属于固定列
                if (String.IsNullOrEmpty(e.Row.Cells[j].Attributes["style"]) || e.Row.Cells[j].Attributes["style"].IndexOf("position: relative;") == -1)
{
e.Row.Cells[j].Attributes.Add("style", " position: relative; top: expression(this.offsetParent.scrollTop);");
}
// 该单元格属于固定列
                else
{
e.Row.Cells[j].Attributes.Add("style", e.Row.Cells[j].Attributes["style"] + "top: expression(this.offsetParent.scrollTop); z-index: 666;");
}
}
}
}
}

5、重写GridView的Render方法，将GridView用一个div包裹起来。

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/// <summary>
/// Render
/// </summary>
/// <param name="writer"></param>
protected override void Render(HtmlTextWriter writer)
{
// 给GridView一个容器 div
    if (!FixRowCol.TableWidth.IsEmpty || !FixRowCol.TableHeight.IsEmpty)
{
if (FixRowCol.TableWidth.IsEmpty)
FixRowCol.TableWidth = new Unit(100, UnitType.Percentage);
if (FixRowCol.TableHeight.IsEmpty)
FixRowCol.TableHeight = new Unit(100, UnitType.Percentage);
writer.Write("<div style=\"overflow: auto; width: "
+ FixRowCol.TableWidth.ToString() + "; height: "
+ FixRowCol.TableHeight.ToString() + "; position: relative;\">");
}
base.Render(writer);
// </div> 结束
    if (!FixRowCol.TableWidth.IsEmpty || !FixRowCol.TableHeight.IsEmpty)
{
writer.Write("<div>");
}
}

控件使用
添加这个控件到工具箱里，然后拖拽到webform上，设置其FixRowCol下的5个属性即可。IsFixHeader是固定表头否？；FixRowIndices是需要固定的行的索引（用逗号“,”分隔）；FixColumnIndices是需要固定的列的索引（用逗号“,”分隔）；TableWidth是表格的宽度；TableHeight是表格的高度
ObjData.cs

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using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.ComponentModel;
/// <summary>
/// OjbData 的摘要说明
/// </summary>
public class OjbData
{
public OjbData()
{
//
        // TODO: 在此处添加构造函数逻辑
        //
    }
[DataObjectMethod(DataObjectMethodType.Select, true)]
public DataTable Select()
{
DataTable dt = new DataTable();
dt.Columns.Add("no", typeof(string));
dt.Columns.Add("name", typeof(string));
for (int i = 0; i < 30; i++)
{
DataRow dr = dt.NewRow();
dr[0] = "no" + i.ToString().PadLeft(2, '0');
dr[1] = "name" + i.ToString().PadLeft(2, '0');
dt.Rows.Add(dr);
}
return dt;
}
}

Default.aspx

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<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>SmartGridView测试</title>
</head>
<body>
<form id="form1" runat="server">
<yyc:SmartGridView ID="SmartGridView1" runat="server" AutoGenerateColumns="False"
DataSourceID="ObjectDataSource1" Width="100%">
<Columns>
<asp:BoundField DataField="no" HeaderText="序号" SortExpression="no" />
<asp:BoundField DataField="name" HeaderText="名称" SortExpression="name" />
<asp:BoundField DataField="no" HeaderText="序号" SortExpression="no" />
<asp:BoundField DataField="name" HeaderText="名称" SortExpression="name" />
<asp:BoundField DataField="no" HeaderText="序号" SortExpression="no" />
<asp:BoundField DataField="name" HeaderText="名称" SortExpression="name" />
<asp:BoundField DataField="no" HeaderText="序号" SortExpression="no" />
<asp:BoundField DataField="name" HeaderText="名称" SortExpression="name" />
<asp:BoundField DataField="no" HeaderText="序号" SortExpression="no" />
<asp:BoundField DataField="name" HeaderText="名称" SortExpression="name" />
</Columns>
<FixRowCol FixColumnIndices="0,1" FixRowIndices="0" IsFixHeader="True" TableHeight="300px"
TableWidth="300px" />
</yyc:SmartGridView>
<asp:ObjectDataSource ID="ObjectDataSource1" runat="server" SelectMethod="Select"
TypeName="OjbData"></asp:ObjectDataSource>
</form>
</body>
</html>