：GridView 空记录时显示 Header

地址：http://www.star1168.com/blog/index.php/archives/158

 

public class GridViewEx : GridView

{



    // 用于保存 Columns 中列

    private ArrayList _columns;





    [DefaultValue(true)]

    public bool ForceShowHeader

    {

        get

        {

            object o = ViewState["ForceShowHeader"];

            if (o != null)

                return (bool)o;



            return true;

        }

        set

        {

            ViewState["ForceShowHeader"] = value;

        }

    }



    protected override ICollection CreateColumns(PagedDataSource dataSource, bool useDataSource)

    {

        if (_columns != null)

            return _columns;



        _columns = (ArrayList)base.CreateColumns(dataSource, useDataSource);

        return _columns;

    }



    protected override int CreateChildControls(IEnumerable dataSource, bool dataBinding)

    {

        int count = base.CreateChildControls(dataSource, dataBinding);



        if (ForceShowHeader && count == 0)

        {

            Table table;

            if (Controls.Count == 0)

            {

                table = CreateChildTable();

                Controls.Add(table);

            }

            else

            {

                table = Controls[0] as Table;

                if (table == null)

                    throw new ApplicationException("第一个子控件不为 Table 控件");

            }



            DataControlField[] fields = new DataControlField[_columns.Count];

            _columns.CopyTo(fields, 0);



            // 创建表示头并初始化此行

            GridViewRow headerRow = CreateRow(-1, -1, DataControlRowType.Header, DataControlRowState.Normal);

            InitializeRow(headerRow, fields);



            // 引发 RowCreated 事件

            GridViewRowEventArgs args = new GridViewRowEventArgs(headerRow);

            OnRowCreated(args);



            // 把表头行添加到表格中

            table.Rows.AddAt(0, headerRow);

        }



        return count;

    }

}

在使用的时候，把 ForceShowHeader 属性设置为 true 即可（默认值是 true