GridView当数据源为空时仍显示表头

GridView当数据源为空时如何实现显示表头 解决: 方法一:采用其EmptyTemplate来实现,模版中写一个静态的table; 缺点: 麻烦,每个GridVIew都需要设置一下. 方法二: 若数据源为DataTable,则当无数据时,始终返回一个空行的DataTable; 若数据源是集合类(ArrayList,List<T>等),无数据时,生成一个空的实体,加入到集合类中. 缺点: 还是麻烦. 方法三: 也是要给大家介绍的方法: 扩展GridView来实现.继承GridVie,重写Render方法,当其数据源为空时做一下处理,直接看代码吧:     /// <summary>     /// GridView 扩展控件     /// @author:[email protected]     /// </summary>      public class GridView : System.Web.UI.WebControls.GridView      {                 private bool _enableEmptyContentRender = true ;          // / <summary>          // / 是否数据为空时显示标题行          // / </summary>          public bool EnableEmptyContentRender          {              set { _enableEmptyContentRender = value; }              get { return _enableEmptyContentRender; }          }          private string _EmptyDataCellCssClass ;          // / <summary>          // / 为空时信息单元格样式类          // / </summary>          public string EmptyDataCellCssClass          {              set { _EmptyDataCellCssClass = value ; }              get { return _EmptyDataCellCssClass ; }          }          // / <summary>          // / 为空时输出内容          // / </summary>          // / <param name="writer"></param>          protected virtual void RenderEmptyContent(HtmlTextWriter writer)          {              Table t = new Table(); //create a table              t.CssClass = this .CssClass; //copy all property              t.GridLines = this .GridLines;              t.BorderStyle = this .BorderStyle;              t.BorderWidth = this .BorderWidth;              t.CellPadding = this .CellPadding;              t.CellSpacing = this .CellSpacing;              t.HorizontalAlign = this .HorizontalAlign;              t.Width = this .Width;              t.CopyBaseAttributes( this );              TableRow row = new TableRow();              t.Rows.Add(row);              foreach (DataControlField f in this .Columns) //generate table header              {                  TableCell cell = new TableCell();                  cell.Text = f.HeaderText;                  cell.CssClass = " TdHeaderStyle1 " ;                  row.Cells.Add(cell);              }              TableRow row2 = new TableRow();              t.Rows.Add(row2);              TableCell msgCell = new TableCell();              msgCell.CssClass = this ._EmptyDataCellCssClass;              if ( this .EmptyDataTemplate != null ) //the second row, use the template              {                  this .EmptyDataTemplate.InstantiateIn(msgCell);              }              else //the second row, use the EmptyDataText              {                  msgCell.Text = this .EmptyDataText;              }              msgCell.HorizontalAlign = HorizontalAlign.Center;              msgCell.ColumnSpan = this .Columns.Count;              row2.Cells.Add(msgCell);              t.RenderControl(writer);         }          protected override void    Render(HtmlTextWriter writer)          {              if ( _enableEmptyContentRender && ( this .Rows.Count == 0 || this .Rows[ 0 ].RowType == DataControlRowType.EmptyDataRow) )              {                  RenderEmptyContent(writer);              }              else              {                  base.Render(writer);              }          }        } }   另解1： DataTable dt_Test = new DataTable(); dt_Test = obj.GetList(); if(dt_Test.Rows.Count == 0) {     dt_Test.Rows.Add(dt.NewRow());     gv_Test. DataSource = dt_Test;     gv_Test.DataBind();     int columnCount = dt_Test.Rows[0].Cells.Count;     gv_Test.Rows[0].Cells.Clear();     gv_Test.Rows[0].Cells.Add(new TableCell());     gv_Test.Rows[0].Cells[0].ColumnSpan = columnCount;     gv_Test.Rows[0].Cells[0].Text = "没有记录";     gv_Test.Rows[0].Cells[0].Style.Add("text-align","center"); } else { gv_Test. DataSource = dt_Test; gv_Test.DataBind(); } 另解2： private void ShowNullTable(GridView grd)         {             if (grd.Rows.Count > 0) return; //有数据，不要处理             if (grd.DataSource != null)             {                 if (((DataTable)grd.DataSource).Rows.Count > 0)                 {                     return;                 }             }             GridViewRow row = new GridViewRow(-1, -1, DataControlRowType.EmptyDataRow, DataControlRowState.Normal);             foreach (DataControlField field in grd.Columns)             {                 TableCell cell = new TableCell();                 cell.Text = field.HeaderText;                 cell.Width = field.HeaderStyle.Width;                 cell.Height = field.HeaderStyle.Height;                 cell.ForeColor = field.HeaderStyle.ForeColor;                 cell.Font.Size = field.HeaderStyle.Font.Size;                 cell.Font.Bold = field.HeaderStyle.Font.Bold;                 cell.Font.Name = field.HeaderStyle.Font.Name;                 cell.Font.Strikeout = field.HeaderStyle.Font.Strikeout;                 cell.Font.Underline = field.HeaderStyle.Font.Underline;                 cell.BackColor = field.HeaderStyle.BackColor;                 cell.VerticalAlign = field.HeaderStyle.VerticalAlign;                 cell.HorizontalAlign = field.HeaderStyle.HorizontalAlign;                 cell.CssClass = field.HeaderStyle.CssClass;                 cell.BorderColor = field.HeaderStyle.BorderColor;                 cell.BorderStyle = field.HeaderStyle.BorderStyle;                 cell.BorderWidth = field.HeaderStyle.BorderWidth;                 row.Cells.Add(cell);             }             TableItemStyle headStyle = grd.HeaderStyle;             TableItemStyle emptyStyle = grd.EmptyDataRowStyle;             emptyStyle.Width = headStyle.Width;             emptyStyle.Height = headStyle.Height;             emptyStyle.ForeColor = headStyle.ForeColor;             emptyStyle.Font.Size = headStyle.Font.Size;             emptyStyle.Font.Bold = headStyle.Font.Bold;             emptyStyle.Font.Name = headStyle.Font.Name;             emptyStyle.Font.Strikeout = headStyle.Font.Strikeout;             emptyStyle.Font.Underline = headStyle.Font.Underline;             emptyStyle.BackColor = headStyle.BackColor;             emptyStyle.VerticalAlign = headStyle.VerticalAlign;             emptyStyle.HorizontalAlign = headStyle.HorizontalAlign;             emptyStyle.CssClass = headStyle.CssClass;             emptyStyle.BorderColor = headStyle.BorderColor;             emptyStyle.BorderStyle = headStyle.BorderStyle;             emptyStyle.BorderWidth = headStyle.BorderWidth;             if (grd.Controls.Count == 0)             {                 grd.Page.Response.Write("<script language='javascript'>alert('必须在初始化表格类之前执行DataBind方法并设置EmptyDataText属性不为空!');</script>");             }             else             {                 grd.Controls[0].Controls.Clear(); //删除没数据时的提示                 grd.Controls[0].Controls.AddAt(0, row);                 GridViewRow newRow = new GridViewRow(0, 0, DataControlRowType.DataRow, DataControlRowState.Normal);                 newRow.Cells.Add(new TableCell());                 newRow.Cells[0].ColumnSpan = Columns.Count;                 newRow.Cells[0].HorizontalAlign = HorizontalAlign.Center;                 newRow.Cells[0].Text = EmptyDataText;                 grd.Controls[0].Controls.Add(newRow);             }         }