How to display the table header when the data source of the GridView is empty Solution: Method 1: Use its EmptyTemplate to implement it. Write a static table in the template;
Disadvantage: It is troublesome. You need to set each GridVIew. Method 2: if the data source is able, a blank row of DataTable is always returned when no data exists;
If the data source is a collection class (ArrayList, List <T>, etc.), when no data exists, an empty entity is generated and added to the Collection class.
Disadvantage: it is still troublesome. Method 3:
This is also the method to introduce: extend the GridView to implement. inherit GridVie and rewrite the Render method. When the data source is empty, perform the following processing: /// <Summary>
/// GridView extension control
/// @ Author: jianyi0115@163.com
/// </Summary>
Public class GridView: System. Web. UI. WebControls. GridView
{
Private bool _ enableEmptyContentRender = true;
/// <Summary>
/// Whether the title line is displayed when the data is null
/// </Summary>
Public bool EnableEmptyContentRender
{
Set {_ enableEmptyContentRender = value ;}
Get {return _ enableEmptyContentRender ;}
}Private string _ EmptyDataCellCssClass;
/// <Summary>
/// Information cell style class when it is null
/// </Summary>
Public string EmptyDataCellCssClass
{
Set {_ EmptyDataCellCssClass = value ;}
Get {return _ EmptyDataCellCssClass ;}
} /// <Summary>
/// Output content when it is null
/// </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 );
}
} }
} Solution 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 = "no record "; Gv_Test.Rows [0]. Cells [0]. Style. Add ("text-align", "center ");
} Else { Gv_Test. DataSource = dt_Test; Gv_Test.DataBind (); } Solution 2: Private void ShowNullTable (GridView grd)
{
If (grd. Rows. Count> 0) return; // if there is data, do not process it
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 (' The DataBind method must be executed before the table class is initialized and the EmptyDataText attribute is set to not empty! '); </Script> ");
}
Else
{
Grd. Controls [0]. Controls. Clear (); // message displayed when no data is deleted
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 );
} } |
