是否有一种简短的方法可以使FooterTemplate（在GridView中）始终可见，即使DataSource为空？
答案 0 :(得分：7)
我也遇到了麻烦。来自Alconja的链接有很多帮助（感谢Alconja），但GridView.FooterRow则返回null。我需要它来从页脚插入新记录。
这是我的最终解决方案。现在，即使网格为空，也可以从页脚插入数据。
GridViewExtended.cs （App_Code文件夹中的一个类）：
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Text;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace YourNamespace
{
public class GridViewExtended : GridView
{
#region Public Properties
[Category("Behavior")]
[Themeable(true)]
[Bindable(BindableSupport.No)]
public bool ShowFooterWhenEmpty
{
get
{
if (this.ViewState["ShowFooterWhenEmpty"] == null)
{
this.ViewState["ShowFooterWhenEmpty"] = false;
}
return (bool)this.ViewState["ShowFooterWhenEmpty"];
}
set
{
this.ViewState["ShowFooterWhenEmpty"] = value;
}
}
#endregion
private GridViewRow _footerRow2;
public override GridViewRow FooterRow
{
get
{
GridViewRow f = base.FooterRow;
if (f != null)
return f;
else
return _footerRow2;
}
}
protected override int CreateChildControls(System.Collections.IEnumerable dataSource, bool dataBinding)
{
int rows = base.CreateChildControls(dataSource, dataBinding);
// no data rows created, create empty table if enabled
if (rows == 0 && (this.ShowFooterWhenEmpty))
{
// create the table
Table table = this.CreateChildTable();
DataControlField[] fields;
if (this.AutoGenerateColumns)
{
PagedDataSource source = new PagedDataSource();
source.DataSource = dataSource;
System.Collections.ICollection autoGeneratedColumns = this.CreateColumns(source, true);
fields = new DataControlField[autoGeneratedColumns.Count];
autoGeneratedColumns.CopyTo(fields, 0);
}
else
{
fields = new DataControlField[this.Columns.Count];
this.Columns.CopyTo(fields, 0);
}
if (this.ShowHeaderWhenEmpty)
{
// create a new header row
GridViewRow headerRow = base.CreateRow(-1, -1, DataControlRowType.Header, DataControlRowState.Normal);
this.InitializeRow(headerRow, fields);
// add the header row to the table
table.Rows.Add(headerRow);
}
// create the empty row
GridViewRow emptyRow = new GridViewRow(-1, -1, DataControlRowType.EmptyDataRow, DataControlRowState.Normal);
TableCell cell = new TableCell();
cell.ColumnSpan = fields.Length;
cell.Width = Unit.Percentage(100);
// respect the precedence order if both EmptyDataTemplate
// and EmptyDataText are both supplied ...
if (this.EmptyDataTemplate != null)
{
this.EmptyDataTemplate.InstantiateIn(cell);
}
else if (!string.IsNullOrEmpty(this.EmptyDataText))
{
cell.Controls.Add(new LiteralControl(EmptyDataText));
}
emptyRow.Cells.Add(cell);
table.Rows.Add(emptyRow);
if (this.ShowFooterWhenEmpty)
{
// create footer row
_footerRow2 = base.CreateRow(-1, -1, DataControlRowType.Footer, DataControlRowState.Normal);
this.InitializeRow(_footerRow2, fields);
// add the footer to the table
table.Rows.Add(_footerRow2);
}
this.Controls.Clear();
this.Controls.Add(table);
}
return rows;
}
}
}
在 aspx 页面中，只需添加
即可<%@ Register TagPrefix="YourPrefix" Namespace="YourNamespace" %>
并将<asp:GridView替换为<YourPrefix:GridViewExtended
希望它有所帮助。
答案 1 :(得分：5)
如果您希望它始终显示，无论内容如何，您是否只能将页脚html放在GridView之外而不是FooterTemplate？
如果出于某种原因这不是一个选项，那么您可以add an null row to your data source if it's empty或subclass the GridView & override the default behaviour。
这是我所知道的唯一选项（虽然自上次使用GridView以来已经有一段时间了。）
答案 2 :(得分：3)
作为之前提到的评论者之一，RowDataBound事件并不会触发页脚。我找到了addresses this issue的另一个代码片段，但除了显示页脚之外，它还显式创建了行（触发RowCreated事件）并将其绑定（触发RowDataBound事件）。
我已使用代码转换器将上面引用的代码转换为c＃并进行了一些小的调整。我还包括了我在逐步完成代码时所做的评论。 RowCreated和RowDataBound事件现在正在触发，我可以在页脚中填充下拉列表。
using System.Linq;
using System.Web.UI.WebControls;
using System.ComponentModel;
namespace WebUI.Controls
{
//modified from https://stackoverflow.com/questions/3437581/show-gridview-footer-on-empty-grid
public class GridViewExtended : GridView
{
private GridViewRow _footerRow;
[DefaultValue(false), Category("Appearance"), Description("Include the footer when the table is empty")]
public bool ShowFooterWhenEmpty { get; set; }
[DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden), Browsable(false)]
public override GridViewRow FooterRow {
get {
if ((this._footerRow == null)) {
this.EnsureChildControls();
}
return this._footerRow;
}
}
protected override int CreateChildControls(System.Collections.IEnumerable dataSource, bool dataBinding)
{
//creates all the rows that would normally be created when instantiating the grid
int returnVal = base.CreateChildControls(dataSource, dataBinding);
//if no rows were created (i.e. returnVal == 0), and we need to show the footer row, then we need to create and bind the footer row.
if (returnVal == 0 && this.ShowFooterWhenEmpty) {
Table table = this.Controls.OfType<Table>().First<Table>();
DataControlField[] dcf = new DataControlField[this.Columns.Count];
this.Columns.CopyTo(dcf, 0);
//creates the footer row
this._footerRow = this.CreateRow(-1, -1, DataControlRowType.Footer, DataControlRowState.Normal, dataBinding, null, dcf, table.Rows, null);
if (!this.ShowFooter) {
_footerRow.Visible = false;
}
}
return returnVal;
}
private GridViewRow CreateRow(int rowIndex, int dataSourceIndex, DataControlRowType rowType, DataControlRowState rowState, bool dataBind, object dataItem, DataControlField[] fields, TableRowCollection rows, PagedDataSource pagedDataSource)
{
GridViewRow row = this.CreateRow(rowIndex, dataSourceIndex, rowType, rowState);
GridViewRowEventArgs e = new GridViewRowEventArgs(row);
if ((rowType != DataControlRowType.Pager)) {
this.InitializeRow(row, fields);
} else {
this.InitializePager(row, fields.Length, pagedDataSource);
}
//if the row has data, sets the data item
if (dataBind) {
row.DataItem = dataItem;
}
//Raises the RowCreated event
this.OnRowCreated(e);
//adds the row to the gridview's row collection
rows.Add(row);
//explicitly binds the data item to the row, including the footer row and raises the RowDataBound event.
if (dataBind) {
row.DataBind();
this.OnRowDataBound(e);
row.DataItem = null;
}
return row;
}
}
}