解决无法获取 GridView 中BoundField 隐藏列值问题
第一种解决方法（本人成功）：在后台页
int num = int.Parse(gv.DataKeys[dr.RowIndex].Values[0].ToString());
第二种解决方法：（摘自 http://www.cnblogs.com/Jinglecat/archive/2007/09/12/813338.html）
在 GridView/DetailsView 中如果 BoundField 的 Visible=false 时, 回发的时候无法此列的值（GridViewRow.Cells[cellIndex].Text将为空)，网上很多朋友提出了各种各样的解决方案，这里整理一下，并提供示例。
未反射 GridView 类，不曾仔细阅读其源码，不知内部实现对于 BoundField（普通绑定列），当此列 Visible=false 时，是未执行绑定计算，还是未保持 ViewState，也许这是就是传说的GridView性能由于DataGrid的一点吧。事实上，这样反而给粗心的开发者带来了“莫名其妙”的问题。DataGrid 中 BoundColumn 不存在此问题。
MSDN 对此是这样的说明：
备注使用 Visible 属性显示或隐藏数据绑定控件中的 DataControlField 对象。如果 Visible 属性为 false，则不显示数据值并且不做到客户端的往返行程。如果要往返不可见字段的数据，请将字段名添加到数据绑定控件的 DataKeyNames 属性。
http://msdn2.microsoft.com/zh-cn/library/system.web.ui.webcontrols.datacontrolfield.visible(VS.80).aspx
说明：BoundField 类继承自 DataControlField 类。
事实上，实际项目中，我几乎没有使用隐藏列的经验，即使在 1.x 的 DataGrid 中，为了记录某些有用的隐藏信息，我一般使用模板列中嵌套控件，如label 并设置其visible=false 最佳当然是用 input type=hidden runat=server（注：1.x 中没有 asp:hiddenfield 控件)。
而 2.0 ，最佳的方案，当然是使用 DataKeys 来存储，不像DataGrid.DataKey ，GridView/DetailsView.DataKeys 可以存储多个值。
以下为示例代码，代码包含各种方案的“自说明”注释，不再做过多的解释。
代码
<%
@ Page Language
=
"
C#
"
%>
<% @ Import Namespace = " System.Data " %>
<%-- http: // community.csdn.net/Expert/TopicView3.asp?id=5646507--%>
<! DOCTYPE html PUBLIC " -//W3C//DTD XHTML 1.0 Transitional//EN " " http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd " >
< script runat = " server " >
protected void Page_Load( object sender, EventArgs e)
{
if ( ! IsPostBack) {
LoadProductData();
}
}
protected void GridView1_RowDataBound( object sender, GridViewRowEventArgs e)
{
// 客户端 CSS 控制隐藏，不安全，毕竟数据还是呈现到客户端了
e.Row.Cells[ 3 ].Style.Add(HtmlTextWriterStyle.Display, " none " );
// 设置单元格隐藏, TableCell.Visible=false, OK
e.Row.Cells[ 4 ].Visible = false ;
}
protected void GridView1_RowCommand( object sender, GridViewCommandEventArgs e)
{
int rowIndex = - 1 ;
switch (e.CommandName) {
case " Select " :
rowIndex = Convert.ToInt32(e.CommandArgument);
GridViewRow row = GridView1.Rows[rowIndex];
Response.Write(String.Format( " <pre style='color:red'>您选择了第 {0} 行\n当前行 ProductId={1}, CategoryId={2}（两者均由DataKeys获取）\n " ,
(row.RowIndex + 1 ),
GridView1.DataKeys[rowIndex].Values[ " ProductId " ],
GridView1.DataKeys[rowIndex].Values[ " CategoryId " ]));
for ( int columnIndex = 0 ; columnIndex < GridView1.Columns.Count; columnIndex ++ ) {
DataControlField field = GridView1.Columns[columnIndex];
string text = null ;
if (field is BoundField) {
text = row.Cells[columnIndex].Text;
}
else if (field is TemplateField) {
Label lbl = row.Cells[columnIndex].FindControl( " lblProductID " ) as Label;
if (lbl != null ) {
text = lbl.Text;
}
else {
text = row.Cells[columnIndex].Text;
}
}
Response.Write(String.Format( " {0}#Type={1}#Visible={2}#CanGetText={3}#Text={4}\n " ,
field.HeaderText, field.GetType().Name.ToString(), field.Visible, ! String.IsNullOrEmpty(text), text));
}
Response.Write( " </pre> " );
break ;
}
}
void LoadProductData()
{
DataTable dt = CreateProductTable();
GridView1.DataSource = dt;
GridView1.DataBind();
}
#region sample data
static DataTable CreateProductTable()
{
DataTable tbl = new DataTable( " Products " );
tbl.Columns.Add( " ProductID " , typeof ( int ));
tbl.Columns.Add( " ProductName " , typeof ( string ));
tbl.Columns.Add( " CategoryID " , typeof ( int ));
DataRow row = tbl.NewRow();
row[ 0 ] = 1 ;
row[ 1 ] = " Chai " ;
row[ 2 ] = 1 ;
tbl.Rows.Add(row);
row = tbl.NewRow();
row[ 0 ] = 2 ;
row[ 1 ] = " Chang " ;
row[ 2 ] = 1 ;
tbl.Rows.Add(row);
row = tbl.NewRow();
row[ 0 ] = 3 ;
row[ 1 ] = " Aniseed Syrup " ;
row[ 2 ] = 2 ;
tbl.Rows.Add(row);
row = tbl.NewRow();
row[ 0 ] = 4 ;
row[ 1 ] = " Chef Anton's Cajun Seasoning " ;
row[ 2 ] = 2 ;
tbl.Rows.Add(row);
row = tbl.NewRow();
row[ 0 ] = 5 ;
row[ 1 ] = " Chef Anton's Gumbo Mix " ;
row[ 2 ] = 2 ;
tbl.Rows.Add(row);
row = tbl.NewRow();
row[ 0 ] = 47 ;
row[ 1 ] = " Zaanse koeken " ;
row[ 2 ] = 3 ;
tbl.Rows.Add(row);
row = tbl.NewRow();
row[ 0 ] = 48 ;
row[ 1 ] = " Chocolade " ;
row[ 2 ] = 3 ;
tbl.Rows.Add(row);
row = tbl.NewRow();
row[ 0 ] = 49 ;
row[ 1 ] = " Maxilaku " ;
row[ 2 ] = 3 ;
tbl.Rows.Add(row);
return tbl;
}
#endregion
protected void Button1_Click( object sender, EventArgs e)
{
LoadProductData();
}
</ script >
< html xmlns = " http://www.w3.org/1999/xhtml " >
< head runat = " server " >
< title > Demo6_AccessHiddenGridViewColumnValue </ title >
</ head >
< body >
< form id = " form1 " runat = " server " >
< div >
< asp:GridView ID = " GridView1 " DataKeyNames = " ProductId,CategoryId " runat = " server " AutoGenerateColumns = " False " OnRowCommand = " GridView1_RowCommand " OnRowDataBound = " GridView1_RowDataBound " CellPadding = " 4 " ForeColor = " #333333 " >
< Columns >
< asp:BoundField DataField = " ProductID " HeaderText = " 列0 正常状态 " />
< asp:BoundField DataField = " ProductID " HeaderText = " 列1 直接设置Visible=false 无法获取值 " Visible = " False " />
< asp:BoundField DataField = " ProductID " HeaderText = " 列2 width=0 客户端依然呈现无效 " >
< ItemStyle Width = " 0px " />
</ asp:BoundField >
< asp:BoundField DataField = " ProductID " HeaderText = " 列3 客户端 CSS 控制隐藏，不安全，毕竟数据还是呈现到客户端了 " />
< asp:BoundField DataField = " ProductID " HeaderText = " 列4 设置单元格隐藏, TableCell.Visible=false, OK " />
< asp:TemplateField HeaderText = " 列5 模板列直接调用 Eval " Visible = " False " >
< ItemTemplate >
<% # Eval( " ProductID " ) %>
</ ItemTemplate >
</ asp:TemplateField >
< asp:TemplateField HeaderText = " 列6 模板列嵌入 Label " Visible = " False " >
< ItemTemplate >
< asp:label ID = " lblProductID " runat = " server " Text = ' <%# Eval("ProductID") %> ' />
</ ItemTemplate >
</ asp:TemplateField >
< asp:BoundField DataField = " ProductName " HeaderText = " 列7 " />
< asp:ButtonField CommandName = " Select " Text = " Select " HeaderText = " 列8 按钮 " />
</ Columns >
< FooterStyle BackColor = " #990000 " Font - Bold = " True " ForeColor = " White " />
< RowStyle BackColor = " #FFFBD6 " ForeColor = " #333333 " />
< SelectedRowStyle BackColor = " #FFCC66 " Font - Bold = " True " ForeColor = " Navy " />
< PagerStyle BackColor = " #FFCC66 " ForeColor = " #333333 " HorizontalAlign = " Center " />
< HeaderStyle BackColor = " #990000 " Font - Bold = " True " ForeColor = " White " />
< AlternatingRowStyle BackColor = " White " />
</ asp:GridView ></ div >
< asp:Button ID = " Button1 " runat = " server " OnClick = " Button1_Click " Text = " 重新绑定数据 " />
</ form >
</ body >
</ html >
<% @ Import Namespace = " System.Data " %>
<%-- http: // community.csdn.net/Expert/TopicView3.asp?id=5646507--%>
<! DOCTYPE html PUBLIC " -//W3C//DTD XHTML 1.0 Transitional//EN " " http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd " >
< script runat = " server " >
protected void Page_Load( object sender, EventArgs e)
{
if ( ! IsPostBack) {
LoadProductData();
}
}
protected void GridView1_RowDataBound( object sender, GridViewRowEventArgs e)
{
// 客户端 CSS 控制隐藏，不安全，毕竟数据还是呈现到客户端了
e.Row.Cells[ 3 ].Style.Add(HtmlTextWriterStyle.Display, " none " );
// 设置单元格隐藏, TableCell.Visible=false, OK
e.Row.Cells[ 4 ].Visible = false ;
}
protected void GridView1_RowCommand( object sender, GridViewCommandEventArgs e)
{
int rowIndex = - 1 ;
switch (e.CommandName) {
case " Select " :
rowIndex = Convert.ToInt32(e.CommandArgument);
GridViewRow row = GridView1.Rows[rowIndex];
Response.Write(String.Format( " <pre style='color:red'>您选择了第 {0} 行\n当前行 ProductId={1}, CategoryId={2}（两者均由DataKeys获取）\n " ,
(row.RowIndex + 1 ),
GridView1.DataKeys[rowIndex].Values[ " ProductId " ],
GridView1.DataKeys[rowIndex].Values[ " CategoryId " ]));
for ( int columnIndex = 0 ; columnIndex < GridView1.Columns.Count; columnIndex ++ ) {
DataControlField field = GridView1.Columns[columnIndex];
string text = null ;
if (field is BoundField) {
text = row.Cells[columnIndex].Text;
}
else if (field is TemplateField) {
Label lbl = row.Cells[columnIndex].FindControl( " lblProductID " ) as Label;
if (lbl != null ) {
text = lbl.Text;
}
else {
text = row.Cells[columnIndex].Text;
}
}
Response.Write(String.Format( " {0}#Type={1}#Visible={2}#CanGetText={3}#Text={4}\n " ,
field.HeaderText, field.GetType().Name.ToString(), field.Visible, ! String.IsNullOrEmpty(text), text));
}
Response.Write( " </pre> " );
break ;
}
}
void LoadProductData()
{
DataTable dt = CreateProductTable();
GridView1.DataSource = dt;
GridView1.DataBind();
}
#region sample data
static DataTable CreateProductTable()
{
DataTable tbl = new DataTable( " Products " );
tbl.Columns.Add( " ProductID " , typeof ( int ));
tbl.Columns.Add( " ProductName " , typeof ( string ));
tbl.Columns.Add( " CategoryID " , typeof ( int ));
DataRow row = tbl.NewRow();
row[ 0 ] = 1 ;
row[ 1 ] = " Chai " ;
row[ 2 ] = 1 ;
tbl.Rows.Add(row);
row = tbl.NewRow();
row[ 0 ] = 2 ;
row[ 1 ] = " Chang " ;
row[ 2 ] = 1 ;
tbl.Rows.Add(row);
row = tbl.NewRow();
row[ 0 ] = 3 ;
row[ 1 ] = " Aniseed Syrup " ;
row[ 2 ] = 2 ;
tbl.Rows.Add(row);
row = tbl.NewRow();
row[ 0 ] = 4 ;
row[ 1 ] = " Chef Anton's Cajun Seasoning " ;
row[ 2 ] = 2 ;
tbl.Rows.Add(row);
row = tbl.NewRow();
row[ 0 ] = 5 ;
row[ 1 ] = " Chef Anton's Gumbo Mix " ;
row[ 2 ] = 2 ;
tbl.Rows.Add(row);
row = tbl.NewRow();
row[ 0 ] = 47 ;
row[ 1 ] = " Zaanse koeken " ;
row[ 2 ] = 3 ;
tbl.Rows.Add(row);
row = tbl.NewRow();
row[ 0 ] = 48 ;
row[ 1 ] = " Chocolade " ;
row[ 2 ] = 3 ;
tbl.Rows.Add(row);
row = tbl.NewRow();
row[ 0 ] = 49 ;
row[ 1 ] = " Maxilaku " ;
row[ 2 ] = 3 ;
tbl.Rows.Add(row);
return tbl;
}
#endregion
protected void Button1_Click( object sender, EventArgs e)
{
LoadProductData();
}
</ script >
< html xmlns = " http://www.w3.org/1999/xhtml " >
< head runat = " server " >
< title > Demo6_AccessHiddenGridViewColumnValue </ title >
</ head >
< body >
< form id = " form1 " runat = " server " >
< div >
< asp:GridView ID = " GridView1 " DataKeyNames = " ProductId,CategoryId " runat = " server " AutoGenerateColumns = " False " OnRowCommand = " GridView1_RowCommand " OnRowDataBound = " GridView1_RowDataBound " CellPadding = " 4 " ForeColor = " #333333 " >
< Columns >
< asp:BoundField DataField = " ProductID " HeaderText = " 列0 正常状态 " />
< asp:BoundField DataField = " ProductID " HeaderText = " 列1 直接设置Visible=false 无法获取值 " Visible = " False " />
< asp:BoundField DataField = " ProductID " HeaderText = " 列2 width=0 客户端依然呈现无效 " >
< ItemStyle Width = " 0px " />
</ asp:BoundField >
< asp:BoundField DataField = " ProductID " HeaderText = " 列3 客户端 CSS 控制隐藏，不安全，毕竟数据还是呈现到客户端了 " />
< asp:BoundField DataField = " ProductID " HeaderText = " 列4 设置单元格隐藏, TableCell.Visible=false, OK " />
< asp:TemplateField HeaderText = " 列5 模板列直接调用 Eval " Visible = " False " >
< ItemTemplate >
<% # Eval( " ProductID " ) %>
</ ItemTemplate >
</ asp:TemplateField >
< asp:TemplateField HeaderText = " 列6 模板列嵌入 Label " Visible = " False " >
< ItemTemplate >
< asp:label ID = " lblProductID " runat = " server " Text = ' <%# Eval("ProductID") %> ' />
</ ItemTemplate >
</ asp:TemplateField >
< asp:BoundField DataField = " ProductName " HeaderText = " 列7 " />
< asp:ButtonField CommandName = " Select " Text = " Select " HeaderText = " 列8 按钮 " />
</ Columns >
< FooterStyle BackColor = " #990000 " Font - Bold = " True " ForeColor = " White " />
< RowStyle BackColor = " #FFFBD6 " ForeColor = " #333333 " />
< SelectedRowStyle BackColor = " #FFCC66 " Font - Bold = " True " ForeColor = " Navy " />
< PagerStyle BackColor = " #FFCC66 " ForeColor = " #333333 " HorizontalAlign = " Center " />
< HeaderStyle BackColor = " #990000 " Font - Bold = " True " ForeColor = " White " />
< AlternatingRowStyle BackColor = " White " />
</ asp:GridView ></ div >
< asp:Button ID = " Button1 " runat = " server " OnClick = " Button1_Click " Text = " 重新绑定数据 " />
</ form >
</ body >
</ html >