扩展 GridView 控件 无数据时显示标题列 : C# Version

原文源地址：扩展 GridView 控件 - 无数据时显示标题列 :VB.net Version

此文章，我一看觉得在平时还是比较有用的。所以做一下C# Convert VB.net

(仅针对于新手，需要者浏览)

Page Code

 <gvExtrend:GridViewEmptyHeader ID="gvEmptyHeader" runat="server" AutoGenerateColumns="False"
            EmptyShowHeader="True" EmptyDataText="Empty Data" AllowPaging="True" 
            DataKeyNames="ProductID" DataSourceID="SqlDataSource1">
            <Columns>
                <asp:BoundField DataField="ProductID" HeaderText="ProductID" ReadOnly="True" 
                    SortExpression="ProductID" />
                <asp:BoundField DataField="ProductName" HeaderText="ProductName" 
                    SortExpression="ProductName" />
                <asp:BoundField DataField="SupplierID" HeaderText="SupplierID" 
                    SortExpression="SupplierID" />
            </Columns>
        </gvExtrend:GridViewEmptyHeader>
        <asp:SqlDataSource ID="SqlDataSource1" runat="server" 
            ConnectionString="Data Source=.\sqlexpress;Initial Catalog=Northwind;Integrated Security=True" 
            ProviderName="System.Data.SqlClient" 
            SelectCommand="SELECT [ProductID], [ProductName], [SupplierID] FROM [Alphabetical list of products] WHERE ([CategoryID] = @CategoryID)">
            <SelectParameters>
                <asp:Parameter DefaultValue="99999" Name="CategoryID" Type="Int32" />
            </SelectParameters>
        </asp:SqlDataSource>

Web.Config 添加注册Tag

<pages>
   <controls>
         <add tagPrefix="gvExtrend" namespace="GridViewExtrend" assembly="GridViewExtrend"/>
   </controls>
</pages>

GridViewExtrend Source

namespace GridViewExtrend
{
    using System.Web.UI.WebControls;
    using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.Text;
    using System.Web.UI;
    using System.Drawing;
    using System.Collections;

    [Description("GridViewEmptyHeader"), ToolboxData("<{0}:GvEmptyHeader runat=server><{0}:GvEmptyHeader>")]
    public class GridViewEmptyHeader : GridView
    {
        private Boolean fEmptyShowHeader = true;

        /**//// <summary>
        /// 无数据时是否显示字段标题
        /// </summary>
        public Boolean EmptyShowHeader
        {
            get
            {
                return fEmptyShowHeader;
            }
            set
            {
                fEmptyShowHeader = value;
            }
        }

        /**//// <summary>
        /// 建立子控件
        /// </summary>
        /// <param name="dataSource"></param>
        /// <param name="dataBinding"></param>
        /// <returns>建立的数据列数目</returns>
        protected override int CreateChildControls(IEnumerable dataSource, bool dataBinding)
        {
            Int32 rowCount;
            Table table = new Table();

            rowCount = base.CreateChildControls(dataSource, dataBinding);

            if (this.fEmptyShowHeader && (rowCount == 0))
            {
                table = CreateEmptyTable();
                Controls.Clear();
                Controls.Add(table);
            }

            return rowCount;
        }

        private Table CreateEmptyTable()
        {
            Table table = new Table();
            GridViewRow gridViewRow;
            TableCell cell = new TableCell();
            Int32 count;
            GridViewRowEventArgs e;

            table = base.CreateChildTable();
            count = this.Columns.Count - 1;

            //Create Title Columns
            gridViewRow = base.CreateRow(-1, -1, DataControlRowType.Header, DataControlRowState.Normal);
            DataControlField[] fields = new DataControlField[count + 1];
            this.Columns.CopyTo(fields, 0);
            this.InitializeRow(gridViewRow, fields);
            e = new GridViewRowEventArgs(gridViewRow);
            this.OnRowCreated(e);
            table.Rows.Add(gridViewRow);

            //Create Empty DataColumns
            gridViewRow = new GridViewRow(-1, -1, DataControlRowType.DataRow, DataControlRowState.Normal);
            cell.ColumnSpan = fields.Length;
            cell.Width = Unit.Percentage(100);
            cell.Text = this.EmptyDataText;
            cell.HorizontalAlign = HorizontalAlign.Center;
            gridViewRow.Cells.Add(cell);
            table.Rows.Add(gridViewRow);

            return table;
        }
    }
}