前一示例的一个问题是，当行可编辑时，主键字段 (au_id)
也呈现为文本输入框。您不希望客户端更改该值，因为需要它来确定更新数据库中的哪一行。幸运的是，可以通过精确指定每一列相对于可编辑行的外观，禁用将此列呈现为文本框。为此需在
DataGrid 的 Columns 集合中定义每一行，使用 BoundColumn 控件分配每一列的数据字段。使用此方法，您可以完全控制列的顺序，以及它们的
ReadOnly 属性。对于 au_id 列，将 ReadOnly 属性设置为 true。当行处于编辑模式时，此列将继续呈现为标签。下面的示例说明此方法。
aspx文件里面加入DataGrid控件半设置属性，代码如下：
<body
MS_POSITIONING="GridLayout">
<form id="form7" method="post"
runat="server">
<asp:Literal id="Message"
runat="server"></asp:Literal>
<ASP:DataGrid id="DataGrid1"
runat="server" Width="800" BackColor="#ccccff" BorderColor="black"
ShowFooter="false" CellPadding="3" CellSpacing="0" Font-Name="Verdana"
Font-Size="8pt" HeaderStyle-BackColor="#aaaadd" OnEditCommand="MyDataGrid_Edit"
OnCancelCommand="MyDataGrid_Cancel" OnUpdateCommand="MyDataGrid_Update"
DataKeyField="au_id"
AutoGenerateColumns="false">
<Columns>
<asp:EditCommandColumn
EditText="编辑" CancelText="取消" UpdateText="更新" ItemStyle-Wrap="false"
/>
<asp:BoundColumn HeaderText="au_id" SortExpression="au_id"
ReadOnly="True" DataField="au_id" ItemStyle-Wrap="false"
/>
<asp:BoundColumn HeaderText="au_lname"
SortExpression="au_lname" DataField="au_lname"
/>
<asp:BoundColumn HeaderText="au_fname"
SortExpression="au_fname" DataField="au_fname"
/>
<asp:BoundColumn HeaderText="phone" SortExpression="phone"
DataField="phone" />
<asp:BoundColumn HeaderText="address"
SortExpression="address" DataField="address" />
<asp:BoundColumn
HeaderText="city" SortExpression="city" DataField="city"
/>
<asp:BoundColumn HeaderText="state" SortExpression="state"
DataField="state" />
<asp:BoundColumn HeaderText="zip"
SortExpression="zip" DataField="zip" />
<asp:BoundColumn
HeaderText="contract" SortExpression="contract" DataField="contract"
/>
</Columns>
</ASP:DataGrid>
</form>
</body>
aspx.cs文件中加入下面代码：
导入using System.Data.SqlClient;
定义SqlConnection
myConnection;
private void Page_Load(object sender, System.EventArgs
e)
{
myConnection = new SqlConnection("user id=sa;password=;initial
catalog=pubs;data source=jeff");
if
(!IsPostBack)
BindGrid();
}
public void MyDataGrid_Edit(Object sender, DataGridCommandEventArgs
E)
{
DataGrid1.EditItemIndex =
(int)E.Item.ItemIndex;
BindGrid();
}
public void MyDataGrid_Cancel(Object sender, DataGridCommandEventArgs
E)
{
DataGrid1.EditItemIndex = -1;
BindGrid();
}
public void MyDataGrid_Update(Object sender, DataGridCommandEventArgs
E)
{
String updateCmd = "UPDATE Authors SET au_id = @Id, au_lname =
@LName, au_fname = @FName, phone = @Phone, "
+ "address = @Address,
city = @City, state = @State, zip = @Zip, contract = @Contract where au_id =
@Id";
SqlCommand myCommand = new SqlCommand(updateCmd,
myConnection);
myCommand.Parameters.Add(new SqlParameter("@Id",
SqlDbType.NVarChar, 11));
myCommand.Parameters.Add(new
SqlParameter("@LName", SqlDbType.NVarChar,
40));
myCommand.Parameters.Add(new SqlParameter("@FName",
SqlDbType.NVarChar, 20));
myCommand.Parameters.Add(new
SqlParameter("@Phone", SqlDbType.NChar,
12));
myCommand.Parameters.Add(new SqlParameter("@Address",
SqlDbType.NVarChar, 40));
myCommand.Parameters.Add(new
SqlParameter("@City", SqlDbType.NVarChar,
20));
myCommand.Parameters.Add(new SqlParameter("@State",
SqlDbType.NChar, 2));
myCommand.Parameters.Add(new SqlParameter("@Zip",
SqlDbType.NChar, 5));
myCommand.Parameters.Add(new
SqlParameter("@Contract",
SqlDbType.NVarChar,1));
myCommand.Parameters["@Id"].Value =
DataGrid1.DataKeys[(int)E.Item.ItemIndex];
String[] cols =
{"@Id","@LName","@FName","@Phone","@Address","@City","@State","@Zip","@Contract"};
int
numCols = E.Item.Cells.Count;
for (int i=2; i<numCols-1; i++)
//跳过第一、第二和最后一列
{
String colvalue
=((TextBox)E.Item.Cells[i].Controls[0]).Text;
//
检查在所需字段中是否有空值
if (i<6 && colvalue == "")
{
Message.Text = "错误：“作者
ID”、“姓名”或“电话”不允许使用空值";
return;
}
myCommand.Parameters[cols[i-1]].Value
= colvalue;
}
//追加最后一行，将 true/false 值转换为 0/1
if
(String.Compare(((TextBox)E.Item.Cells[numCols-1].Controls[0]).Text, "True",
true)==0)
myCommand.Parameters["@Contract"].Value = "1";
else
myCommand.Parameters["@Contract"].Value =
"0";
myCommand.Connection.Open();
try
{
myCommand.ExecuteNonQuery();
Message.Text
= "<b>已更新记录</b><br>" +
updateCmd;
DataGrid1.EditItemIndex =
-1;
}
catch (SqlException e)
{
if
(e.Number == 2627)
Message.Text =
"错误：已存在具有相同主键的记录";
else
Message.Text =
"错误：未能更新记录，请确保正确填写了字段";
}
myCommand.Connection.Close();
BindGrid();
}
public void
BindGrid()
{
SqlDataAdapter myCommand = new SqlDataAdapter("select
* from Authors", myConnection);
DataSet ds = new
DataSet();
myCommand.Fill(ds,
"Authors");
DataGrid1.DataSource=ds.Tables["Authors"].DefaultView;
DataGrid1.DataBind();
}
上一例中BoundColumn 控件不是唯一可以在 DataGrid 的 Columns 集合中设置的控件。还可以指定
TemplateColumn，它使您可以完全控制列的内容。模板的内容可以是任意的；在 DataGrid
的列中可以呈现任何内容，包括服务器控件。下面的示例说明如何使用 TemplateColumn
控件将“State”列呈现为下拉列表并将“Contract”列呈现为复选框 HtmlControl。ASP.NET
数据绑定语法用于输出模板中的数据字段值。注意，有一些棘手的逻辑使下拉列表和复选框反射行中的数据状态。
<%@ Import Namespace="System.Data" %>
<%@ Import
Namespace="System.Data.SqlClient" %>
<html>
<script
language="C#" runat="server">
SqlConnection
myConnection;
public Hashtable StateIndex;
protected void Page_Load(Object Src, EventArgs
E)
{
myConnection = new SqlConnection("user id=sa;password=;initial catalog=pubs;data
source=jeff");
if
(!IsPostBack)
BindGrid();
StateIndex = new
Hashtable();
StateIndex["CA"] = 0;
StateIndex["IN"] = 1;
StateIndex["KS"] = 2;
StateIndex["MD"] = 3;
StateIndex["MI"] = 4;
StateIndex["OR"] = 5;
StateIndex["TN"] = 6;
StateIndex["UT"] = 7;
}
public int GetStateIndex(String
stateName)
{
if (StateIndex[stateName] !=
null)
return (int)StateIndex[stateName];
else
return 0;
}
public void MyDataGrid_Edit(Object sender,
DataGridCommandEventArgs E)
{
MyDataGrid.EditItemIndex =
(int)E.Item.ItemIndex;
BindGrid();
}
public void MyDataGrid_Cancel(Object sender,
DataGridCommandEventArgs E)
{
MyDataGrid.EditItemIndex =
-1;
BindGrid();
}
public void MyDataGrid_Update(Object sender,
DataGridCommandEventArgs E)
{
String updateCmd = "UPDATE
Authors SET au_id = @Id, au_lname = @LName, au_fname = @FName, phone = @Phone,
"
+
"address = @Address, city = @City, state = @State, zip = @Zip, contract =
@Contract where au_id = @Id";
SqlCommand myCommand = new SqlCommand(updateCmd,
myConnection);
myCommand.Parameters.Add(new SqlParameter("@Id", SqlDbType.NVarChar,
11));
myCommand.Parameters.Add(new
SqlParameter("@LName", SqlDbType.NVarChar,
40));
myCommand.Parameters.Add(new
SqlParameter("@FName", SqlDbType.NVarChar,
20));
myCommand.Parameters.Add(new
SqlParameter("@Phone", SqlDbType.NChar,
12));
myCommand.Parameters.Add(new
SqlParameter("@Address", SqlDbType.NVarChar,
40));
myCommand.Parameters.Add(new
SqlParameter("@City", SqlDbType.NVarChar,
20));
myCommand.Parameters.Add(new
SqlParameter("@State", SqlDbType.NChar,
2));
myCommand.Parameters.Add(new
SqlParameter("@Zip", SqlDbType.NChar,
5));
myCommand.Parameters.Add(new
SqlParameter("@Contract",
SqlDbType.NVarChar,1));
myCommand.Parameters["@Id"].Value =
MyDataGrid.DataKeys[(int)E.Item.ItemIndex];
String[] cols =
{"LName","FName","Phone","Address","City","Zip"};
for (int i=0; i<6; i++)
{
String
colvalue = ((TextBox)E.Item.FindControl("edit_" +
cols[i])).Text;
//
检查在所需字段中是否有空值
if (i<3 && colvalue ==
"")
{
Message.InnerHtml =
"错误：“姓名”或“电话”不允许使用空值";
Message.Style["color"] =
"red";
return;
}
myCommand.Parameters["@" + cols[i]].Value =
colvalue;
}
myCommand.Parameters["@State"].Value =
((DropDownList)E.Item.FindControl("edit_State")).SelectedItem.ToString();
if
(((CheckBox)E.Item.FindControl("edit_Contract")).Checked ==
true)
myCommand.Parameters["@Contract"].Value =
"1";
else
myCommand.Parameters["@Contract"].Value =
"0";
myCommand.Connection.Open();
try
{
myCommand.ExecuteNonQuery();
Message.InnerHtml = "<b>已更新记录</b><br>" +
updateCmd;
MyDataGrid.EditItemIndex = -1;
}
catch (SqlException
e)
{
if
(e.Number ==
2627)
Message.InnerHtml =
"错误：已存在具有相同主键的记录";
else
Message.InnerHtml =
"错误：未能更新记录，请确保正确填写了字段";
Message.Style["color"] = "red";
}
myCommand.Connection.Close();
BindGrid();
}
public void BindGrid()
{
SqlDataAdapter myCommand = new
SqlDataAdapter("select * from Authors",
myConnection);
DataSet ds = new
DataSet();
myCommand.Fill(ds,
"Authors");
MyDataGrid.DataSource=ds.Tables["Authors"].DefaultView;
MyDataGrid.DataBind();
}
</script>
<body style="font: 10.5pt 宋体">
<form
runat="server">
<h3><font
face="宋体">更新具有模板列的数据行</font></h3>
<span
id="Message" EnableViewState="false" style="font: arial 11pt;"
runat="server"/><p>
<ASP:DataGrid
id="MyDataGrid" runat="server"
Width="800"
BackColor="#ccccff"
BorderColor="black"
ShowFooter="false"
CellPadding=3
CellSpacing="0"
Font-Name="Verdana"
Font-Size="8pt"
HeaderStyle-BackColor="#aaaadd"
OnEditCommand="MyDataGrid_Edit"
OnCancelCommand="MyDataGrid_Cancel"
OnUpdateCommand="MyDataGrid_Update"
DataKeyField="au_id"
AutoGenerateColumns="false"
>
<Columns>
<asp:EditCommandColumn EditText="编辑" CancelText="取消" UpdateText="更新"
ItemStyle-Wrap="false"/>
<asp:BoundColumn HeaderText="au_id" SortExpression="au_id" ReadOnly="True"
DataField="au_id"
ItemStyle-Wrap="false"/>
<asp:TemplateColumn HeaderText="au_lname"
SortExpression="au_lname">
<ItemTemplate>
<asp:Label runat="server" Text="<%# DataBinder.Eval(Container.DataItem,
"au_lname")
%>"/>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox runat="server" id="edit_LName" Text="<%#
DataBinder.Eval(Container.DataItem, "au_lname")
%>"/>
</EditItemTemplate>
</asp:TemplateColumn>
<asp:TemplateColumn HeaderText="au_fname"
SortExpression="au_fname">
<ItemTemplate>
<asp:Label runat="server" Text="<%# DataBinder.Eval(Container.DataItem,
"au_fname")
%>"/>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox runat="server" id="edit_FName" Text="<%#
DataBinder.Eval(Container.DataItem, "au_fname")
%>"/>
</EditItemTemplate>
</asp:TemplateColumn>
<asp:TemplateColumn HeaderText="phone"
SortExpression="phone">
<ItemTemplate>
<asp:Label runat="server" Text="<%# DataBinder.Eval(Container.DataItem,
"phone") %>"/>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox runat="server" id="edit_Phone" Text="<%#
DataBinder.Eval(Container.DataItem, "phone")
%>"/>
</EditItemTemplate>
</asp:TemplateColumn>
<asp:TemplateColumn HeaderText="address"
SortExpression="address">
<ItemTemplate>
<asp:Label runat="server" Text="<%# DataBinder.Eval(Container.DataItem,
"address") %>"/>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox runat="server" id="edit_Address" Text="<%#
DataBinder.Eval(Container.DataItem, "address")
%>"/>
</EditItemTemplate>
</asp:TemplateColumn>
<asp:TemplateColumn HeaderText="city"
SortExpression="city">
<ItemTemplate>
<asp:Label runat="server" Text="<%# DataBinder.Eval(Container.DataItem,
"city") %>"/>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox runat="server" id="edit_City" Text="<%#
DataBinder.Eval(Container.DataItem, "city")
%>"/>
</EditItemTemplate>
</asp:TemplateColumn>
<asp:TemplateColumn HeaderText="state"
SortExpression="state">
<ItemTemplate>
<asp:Label runat="server" Text="<%# DataBinder.Eval(Container.DataItem,
"state") %>"/>
</ItemTemplate>
<EditItemTemplate>
<asp:DropDownList runat="server" SelectedIndex="<%#
GetStateIndex(DataBinder.Eval(Container.DataItem, "state").ToString()) %>"
id="edit_State">
<asp:ListItem>CA</asp:ListItem>
<asp:ListItem>IN</asp:ListItem>
<asp:ListItem>KS</asp:ListItem>
<asp:ListItem>MD</asp:ListItem>
<asp:ListItem>MI</asp:ListItem>
<asp:ListItem>OR</asp:ListItem>
<asp:ListItem>TN</asp:ListItem>
<asp:ListItem>UT</asp:ListItem>
</asp:DropDownList>
</EditItemTemplate>
</asp:TemplateColumn>
<asp:TemplateColumn HeaderText="zip"
SortExpression="zip">
<ItemTemplate>
<asp:Label runat="server" Text="<%# DataBinder.Eval(Container.DataItem,
"zip") %>"/>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox runat="server" id="edit_Zip" Text="<%#
DataBinder.Eval(Container.DataItem, "zip")
%>"/>
</EditItemTemplate>
</asp:TemplateColumn>
<asp:TemplateColumn HeaderText="contract"
SortExpression="contract">
<ItemTemplate>
<asp:Label runat="server" Text="<%# DataBinder.Eval(Container.DataItem,
"contract", "{0}")
%>"/>
</ItemTemplate>
<EditItemTemplate>
<asp:CheckBox runat="server" id="edit_Contract" Checked="<%#
DataBinder.Eval(Container.DataItem, "contract")
%>"/>
</EditItemTemplate>
</asp:TemplateColumn>
</Columns>
</ASP:DataGrid>
</form>
</body>
</html>
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