DataList.CancelCommand Ereignis
Definition
Wichtig
Einige Informationen beziehen sich auf Vorabversionen, die vor dem Release ggf. grundlegend überarbeitet werden. Microsoft übernimmt hinsichtlich der hier bereitgestellten Informationen keine Gewährleistungen, seien sie ausdrücklich oder konkludent.
Tritt ein, wenn auf die Schaltfläche Cancel
für ein Element im DataList-Steuerelement geklickt wird.
public:
event System::Web::UI::WebControls::DataListCommandEventHandler ^ CancelCommand;
public event System.Web.UI.WebControls.DataListCommandEventHandler CancelCommand;
member this.CancelCommand : System.Web.UI.WebControls.DataListCommandEventHandler
Public Custom Event CancelCommand As DataListCommandEventHandler
Ereignistyp
Beispiele
Im folgenden Codebeispiel wird veranschaulicht, wie sie einen Handler für das Ereignis angeben und codieren CancelCommand . Alle An einem Element im DataList Steuerelement vorgenommenen Änderungen werden abgebrochen, wenn auf die Cancel
Schaltfläche geklickt wird.
Hinweis
Im folgenden Codebeispiel wird das Einzeldateicodemodell verwendet. Es funktioniert möglicherweise nicht ordnungsgemäß, wenn es direkt in eine CodeBehind-Datei kopiert wird. Dieses Codebeispiel muss in eine leere Textdatei mit einer .aspx-Erweiterung kopiert werden. Weitere Informationen zum Web Forms-Codemodell finden Sie unter ASP.NET Web Forms-Seitencodemodell.
<%@ Page Language="C#" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>DataList Edit Example</title>
<script runat="server">
// The Cart and CartView objects temporarily store the data source
// for the DataList control while the page is being processed.
DataTable Cart = new DataTable();
DataView CartView;
void Page_Load(Object sender, EventArgs e)
{
// With a database, use an select query to retrieve the data.
// Because the data source in this example is an in-memory
// DataTable, retrieve the data from session state if it exists;
// otherwise, create the data source.
GetSource();
// The DataList control maintains state between posts to the server;
// it only needs to be bound to a data source the first time the
// page is loaded or when the data source is updated.
if (!IsPostBack)
{
BindList();
}
}
void BindList()
{
// Set the data source and bind to the DataList control.
ItemsList.DataSource = CartView;
ItemsList.DataBind();
}
void GetSource()
{
// For this example, the data source is a DataTable that
// is stored in session state. If the data source does not exist,
// create it; otherwise, load the data.
if (Session["ShoppingCart"] == null)
{
// Create the sample data.
DataRow dr;
// Define the columns of the table.
Cart.Columns.Add(new DataColumn("Qty", typeof(Int32)));
Cart.Columns.Add(new DataColumn("Item", typeof(String)));
Cart.Columns.Add(new DataColumn("Price", typeof(Double)));
// Store the table in session state to persist its values
// between posts to the server.
Session["ShoppingCart"] = Cart;
// Populate the DataTable with sample data.
for (int i = 1; i <= 9; i++)
{
dr = Cart.NewRow();
if (i % 2 != 0)
{
dr[0] = 2;
}
else
{
dr[0] = 1;
}
dr[1] = "Item " + i.ToString();
dr[2] = (1.23 * (i + 1));
Cart.Rows.Add(dr);
}
}
else
{
// Retrieve the sample data from session state.
Cart = (DataTable)Session["ShoppingCart"];
}
// Create a DataView and specify the field to sort by.
CartView = new DataView(Cart);
CartView.Sort="Item";
return;
}
void Edit_Command(Object sender, DataListCommandEventArgs e)
{
// Set the EditItemIndex property to the index of the item clicked
// in the DataList control to enable editing for that item. Be sure
// to rebind the DataList to the data source to refresh the control.
ItemsList.EditItemIndex = e.Item.ItemIndex;
BindList();
}
void Cancel_Command(Object sender, DataListCommandEventArgs e)
{
// Set the EditItemIndex property to -1 to exit editing mode. Be sure
// to rebind the DataList to the data source to refresh the control.
ItemsList.EditItemIndex = -1;
BindList();
}
void Delete_Command(Object sender, DataListCommandEventArgs e)
{
// Retrieve the name of the item to remove.
String item = ((Label)e.Item.FindControl("ItemLabel")).Text;
// Filter the CartView for the selected item and remove it from
// the data source.
CartView.RowFilter = "Item='" + item + "'";
if (CartView.Count > 0)
{
CartView.Delete(0);
}
CartView.RowFilter = "";
// Set the EditItemIndex property to -1 to exit editing mode. Be sure
// to rebind the DataList to the data source to refresh the control.
ItemsList.EditItemIndex = -1;
BindList();
}
void Update_Command(Object sender, DataListCommandEventArgs e)
{
// Retrieve the updated values from the selected item.
String item = ((Label)e.Item.FindControl("ItemLabel")).Text;
String qty = ((TextBox)e.Item.FindControl("QtyTextBox")).Text;
String price = ((TextBox)e.Item.FindControl("PriceTextBox")).Text;
// With a database, use an update command to update the data.
// Because the data source in this example is an in-memory
// DataTable, delete the old row and replace it with a new one.
// Filter the CartView for the selected item and remove it from
// the data source.
CartView.RowFilter = "Item='" + item + "'";
if (CartView.Count > 0)
{
CartView.Delete(0);
}
CartView.RowFilter = "";
// ***************************************************************
// Insert data validation code here. Make sure to validate the
// values entered by the user before converting to the appropriate
// data types and updating the data source.
// ***************************************************************
// Add a new entry to replace the previous item.
DataRow dr = Cart.NewRow();
dr[0] = qty;
dr[1] = item;
// If necessary, remove the '$' character from the price before
// converting the price to a Double.
if(price[0] == '$')
{
dr[2] = Convert.ToDouble(price.Substring(1));
}
else
{
dr[2] = Convert.ToDouble(price);
}
Cart.Rows.Add(dr);
// Set the EditItemIndex property to -1 to exit editing mode.
// Be sure to rebind the DataList to the data source to refresh
// the control.
ItemsList.EditItemIndex = -1;
BindList();
}
</script>
</head>
<body>
<form id="form1" runat="server">
<h3>DataList Edit Example</h3>
Click <b>Edit</b> to edit the values of the item.
<br /><br />
<asp:DataList id="ItemsList"
GridLines="Both"
RepeatColumns="3"
RepeatDirection="Horizontal"
CellPadding="3"
CellSpacing="0"
OnEditCommand="Edit_Command"
OnUpdateCommand="Update_Command"
OnDeleteCommand="Delete_Command"
OnCancelCommand="Cancel_Command"
runat="server">
<HeaderStyle BackColor="#aaaadd">
</HeaderStyle>
<AlternatingItemStyle BackColor="Gainsboro">
</AlternatingItemStyle>
<EditItemStyle BackColor="yellow">
</EditItemStyle>
<HeaderTemplate>
Items
</HeaderTemplate>
<ItemTemplate>
Item:
<%# DataBinder.Eval(Container.DataItem, "Item") %>
<br />
Quantity:
<%# DataBinder.Eval(Container.DataItem, "Qty") %>
<br />
Price:
<%# DataBinder.Eval(Container.DataItem, "Price", "{0:c}") %>
<br />
<asp:LinkButton id="EditButton"
Text="Edit"
CommandName="Edit"
runat="server"/>
</ItemTemplate>
<EditItemTemplate>
Item:
<asp:Label id="ItemLabel"
Text='<%# DataBinder.Eval(Container.DataItem, "Item") %>'
runat="server"/>
<br />
Quantity:
<asp:TextBox id="QtyTextBox"
Text='<%# DataBinder.Eval(Container.DataItem, "Qty") %>'
runat="server"/>
<br />
Price:
<asp:TextBox id="PriceTextBox"
Text='<%# DataBinder.Eval(Container.DataItem, "Price", "{0:c}") %>'
runat="server"/>
<br />
<asp:LinkButton id="UpdateButton"
Text="Update"
CommandName="Update"
runat="server"/>
<asp:LinkButton id="DeleteButton"
Text="Delete"
CommandName="Delete"
runat="server"/>
<asp:LinkButton id="CancelButton"
Text="Cancel"
CommandName="Cancel"
runat="server"/>
</EditItemTemplate>
</asp:DataList>
</form>
</body>
</html>
<%@ Page Language="VB" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>DataList Edit Example</title>
<script runat="server">
' The Cart and CartView objects temporarily store the data source
' for the DataList control while the page is being processed.
Dim Cart As DataTable = New DataTable()
Dim CartView As DataView
Sub Page_Load(sende As Object, e As EventArgs)
' With a database, use an select query to retrieve the data.
' Because the data source in this example is an in-memory
' DataTable, retrieve the data from session state if it exists;
' otherwise, create the data source.
GetSource()
' The DataGrid control maintains state between posts to the server;
' it only needs to be bound to a data source the first time the
' page is loaded or when the data source is updated.
If Not IsPostBack Then
BindList()
End If
End Sub
Sub BindList()
' Set the data source and bind to the DataList control.
ItemsList.DataSource = CartView
ItemsList.DataBind()
End Sub
Sub GetSource()
' For this example, the data source is a DataTable that
' is stored in session state. If the data source does not exist,
' create it; otherwise, load the data.
If Session("ShoppingCart") Is Nothing Then
' Create the sample data.
Dim dr As DataRow
' Define the columns of the table.
Cart.Columns.Add(new DataColumn("Qty", GetType(Int32)))
Cart.Columns.Add(new DataColumn("Item", GetType(String)))
Cart.Columns.Add(new DataColumn("Price", GetType(Double)))
' Store the table in session state to persist its values
' between posts to the server.
Session("ShoppingCart") = Cart
' Populate the DataTable with sample data.
Dim i As Integer
For i = 1 To 9
dr = Cart.NewRow()
If (i Mod 2) <> 0 Then
dr(0) = 2
Else
dr(0) = 1
End If
dr(1) = "Item " & i.ToString()
dr(2) = (1.23 * (i + 1))
Cart.Rows.Add(dr)
Next i
Else
' Retrieve the sample data from session state.
Cart = CType(Session("ShoppingCart"), DataTable)
End If
' Create a DataView and specify the field to sort by.
CartView = New DataView(Cart)
CartView.Sort="Item"
Return
End Sub
Sub Edit_Command(sender As Object, e As DataListCommandEventArgs)
' Set the EditItemIndex property to the index of the item clicked
' in the DataList control to enable editing for that item. Be sure
' to rebind the DataList to the data source to refresh the control.
ItemsList.EditItemIndex = e.Item.ItemIndex
BindList()
End Sub
Sub Cancel_Command(sender As Object, e As DataListCommandEventArgs)
' Set the EditItemIndex property to -1 to exit editing mode. Be sure
' to rebind the DataList to the data source to refresh the control.
ItemsList.EditItemIndex = -1
BindList()
End Sub
Sub Delete_Command(sender As Object, e As DataListCommandEventArgs)
' Retrieve the name of the item to remove.
Dim item As String = (CType(e.Item.FindControl("ItemLabel"), Label)).Text
' Filter the CartView for the selected item and remove it from
' the data source.
CartView.RowFilter = "Item='" & item & "'"
If CartView.Count > 0 Then
CartView.Delete(0)
End If
CartView.RowFilter = ""
' Set the EditItemIndex property to -1 to exit editing mode. Be sure
' to rebind the DataList to the data source to refresh the control.
ItemsList.EditItemIndex = -1
BindList()
End Sub
Sub Update_Command(sender As Object, e As DataListCommandEventArgs)
' Retrieve the updated values from the selected item.
Dim item As String = _
(CType(e.Item.FindControl("ItemLabel"), Label)).Text
Dim qty As String = _
(CType(e.Item.FindControl("QtyTextBox"), TextBox)).Text
Dim price As String = _
(CType(e.Item.FindControl("PriceTextBox"), TextBox)).Text
' With a database, use an update command to update the data.
' Because the data source in this example is an in-memory
' DataTable, delete the old row and replace it with a new one.
' Filter the CartView for the selected item and remove it from
' the data source.
CartView.RowFilter = "Item='" & item & "'"
If CartView.Count > 0 Then
CartView.Delete(0)
End If
CartView.RowFilter = ""
' ***************************************************************
' Insert data validation code here. Make sure to validate the
' values entered by the user before converting to the appropriate
' data types and updating the data source.
' ***************************************************************
' Add a new entry to replace the previous item.
Dim dr As DataRow = Cart.NewRow()
dr(0) = qty
dr(1) = item
' If necessary, remove the '$' character from the price before
' converting the price to a Double.
If price.Chars(0) = "$" Then
dr(2) = Convert.ToDouble(price.Substring(1))
Else
dr(2) = Convert.ToDouble(price)
End If
Cart.Rows.Add(dr)
' Set the EditItemIndex property to -1 to exit editing mode.
' Be sure to rebind the DataList to the data source to refresh
' the control.
ItemsList.EditItemIndex = -1
BindList()
End Sub
</script>
</head>
<body>
<form id="form1" runat="server">
<h3>DataList Edit Example</h3>
Click <b>Edit</b> to edit the values of the item.
<br /><br />
<asp:DataList id="ItemsList"
GridLines="Both"
RepeatColumns="3"
RepeatDirection="Horizontal"
CellPadding="3"
CellSpacing="0"
OnEditCommand="Edit_Command"
OnUpdateCommand="Update_Command"
OnDeleteCommand="Delete_Command"
OnCancelCommand="Cancel_Command"
runat="server">
<HeaderStyle BackColor="#aaaadd">
</HeaderStyle>
<AlternatingItemStyle BackColor="Gainsboro">
</AlternatingItemStyle>
<EditItemStyle BackColor="yellow">
</EditItemStyle>
<HeaderTemplate>
Items
</HeaderTemplate>
<ItemTemplate>
Item:
<%# DataBinder.Eval(Container.DataItem, "Item") %>
<br />
Quantity:
<%# DataBinder.Eval(Container.DataItem, "Qty") %>
<br />
Price:
<%# DataBinder.Eval(Container.DataItem, "Price", "{0:c}") %>
<br />
<asp:LinkButton id="EditButton"
Text="Edit"
CommandName="Edit"
runat="server"/>
</ItemTemplate>
<EditItemTemplate>
Item:
<asp:Label id="ItemLabel"
Text='<%# DataBinder.Eval(Container.DataItem, "Item") %>'
runat="server"/>
<br />
Quantity:
<asp:TextBox id="QtyTextBox"
Text='<%# DataBinder.Eval(Container.DataItem, "Qty") %>'
runat="server"/>
<br />
Price:
<asp:TextBox id="PriceTextBox"
Text='<%# DataBinder.Eval(Container.DataItem, "Price", "{0:c}") %>'
runat="server"/>
<br />
<asp:LinkButton id="UpdateButton"
Text="Update"
CommandName="Update"
runat="server"/>
<asp:LinkButton id="DeleteButton"
Text="Delete"
CommandName="Delete"
runat="server"/>
<asp:LinkButton id="CancelButton"
Text="Cancel"
CommandName="Cancel"
runat="server"/>
</EditItemTemplate>
</asp:DataList>
</form>
</body>
</html>
<%@ Page Language="C#" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>DataList Edit Example</title>
<script runat="server">
// The Cart and CartView objects temporarily store the data source
// for the DataList control while the page is being processed.
DataTable Cart = new DataTable();
DataView CartView;
void Page_Load(Object sender, EventArgs e)
{
// With a database, use an select query to retrieve the data.
// Because the data source in this example is an in-memory
// DataTable, retrieve the data from session state if it exists;
// otherwise, create the data source.
GetSource();
// The DataList control maintains state between posts to the server;
// it only needs to be bound to a data source the first time the
// page is loaded or when the data source is updated.
if (!IsPostBack)
{
BindList();
}
// Manually register the event-handling methods.
ItemsList.EditCommand +=
new DataListCommandEventHandler(this.Edit_Command);
ItemsList.UpdateCommand +=
new DataListCommandEventHandler(this.Update_Command);
ItemsList.DeleteCommand +=
new DataListCommandEventHandler(this.Delete_Command);
ItemsList.CancelCommand +=
new DataListCommandEventHandler(this.Cancel_Command);
}
void BindList()
{
// Set the data source and bind to the DataList control.
ItemsList.DataSource = CartView;
ItemsList.DataBind();
}
void GetSource()
{
// For this example, the data source is a DataTable that
// is stored in session state. If the data source does not exist,
// create it; otherwise, load the data.
if (Session["ShoppingCart"] == null)
{
// Create the sample data.
DataRow dr;
// Define the columns of the table.
Cart.Columns.Add(new DataColumn("Qty", typeof(Int32)));
Cart.Columns.Add(new DataColumn("Item", typeof(String)));
Cart.Columns.Add(new DataColumn("Price", typeof(Double)));
// Store the table in session state to persist its values
// between posts to the server.
Session["ShoppingCart"] = Cart;
// Populate the DataTable with sample data.
for (int i = 1; i <= 9; i++)
{
dr = Cart.NewRow();
if (i % 2 != 0)
{
dr[0] = 2;
}
else
{
dr[0] = 1;
}
dr[1] = "Item " + i.ToString();
dr[2] = (1.23 * (i + 1));
Cart.Rows.Add(dr);
}
}
else
{
// Retrieve the sample data from session state.
Cart = (DataTable)Session["ShoppingCart"];
}
// Create a DataView and specify the field to sort by.
CartView = new DataView(Cart);
CartView.Sort="Item";
return;
}
void Edit_Command(Object sender, DataListCommandEventArgs e)
{
// Set the EditItemIndex property to the index of the item clicked
// in the DataList control to enable editing for that item. Be sure
// to rebind the DataList to the data source to refresh the control.
ItemsList.EditItemIndex = e.Item.ItemIndex;
BindList();
}
void Cancel_Command(Object sender, DataListCommandEventArgs e)
{
// Set the EditItemIndex property to -1 to exit editing mode. Be sure
// to rebind the DataList to the data source to refresh the control.
ItemsList.EditItemIndex = -1;
BindList();
}
void Delete_Command(Object sender, DataListCommandEventArgs e)
{
// Retrieve the name of the item to remove.
String item = ((Label)e.Item.FindControl("ItemLabel")).Text;
// Filter the CartView for the selected item and remove it from
// the data source.
CartView.RowFilter = "Item='" + item + "'";
if (CartView.Count > 0)
{
CartView.Delete(0);
}
CartView.RowFilter = "";
// Set the EditItemIndex property to -1 to exit editing mode. Be sure
// to rebind the DataList to the data source to refresh the control.
ItemsList.EditItemIndex = -1;
BindList();
}
void Update_Command(Object sender, DataListCommandEventArgs e)
{
// Retrieve the updated values from the selected item.
String item = ((Label)e.Item.FindControl("ItemLabel")).Text;
String qty = ((TextBox)e.Item.FindControl("QtyTextBox")).Text;
String price = ((TextBox)e.Item.FindControl("PriceTextBox")).Text;
// With a database, use an update command to update the data.
// Because the data source in this example is an in-memory
// DataTable, delete the old row and replace it with a new one.
// Filter the CartView for the selected item and remove it from
// the data source.
CartView.RowFilter = "Item='" + item + "'";
if (CartView.Count > 0)
{
CartView.Delete(0);
}
CartView.RowFilter = "";
// ***************************************************************
// Insert data validation code here. Make sure to validate the
// values entered by the user before converting to the appropriate
// data types and updating the data source.
// ***************************************************************
// Add a new entry to replace the previous item.
DataRow dr = Cart.NewRow();
dr[0] = qty;
dr[1] = item;
// If necessary, remove the '$' character from the price before
// converting the price to a Double.
if(price[0] == '$')
{
dr[2] = Convert.ToDouble(price.Substring(1));
}
else
{
dr[2] = Convert.ToDouble(price);
}
Cart.Rows.Add(dr);
// Set the EditItemIndex property to -1 to exit editing mode.
// Be sure to rebind the DataList to the data source to refresh
// the control.
ItemsList.EditItemIndex = -1;
BindList();
}
</script>
</head>
<body>
<form id="form1" runat="server">
<h3>DataList Edit Example</h3>
Click <b>Edit</b> to edit the values of the item.
<br /><br />
<asp:DataList id="ItemsList"
GridLines="Both"
RepeatColumns="3"
RepeatDirection="Horizontal"
CellPadding="3"
CellSpacing="0"
runat="server">
<HeaderStyle BackColor="#aaaadd">
</HeaderStyle>
<AlternatingItemStyle BackColor="Gainsboro">
</AlternatingItemStyle>
<EditItemStyle BackColor="yellow">
</EditItemStyle>
<HeaderTemplate>
Items
</HeaderTemplate>
<ItemTemplate>
Item:
<%# DataBinder.Eval(Container.DataItem, "Item") %>
<br />
Quantity:
<%# DataBinder.Eval(Container.DataItem, "Qty") %>
<br />
Price:
<%# DataBinder.Eval(Container.DataItem, "Price", "{0:c}") %>
<br />
<asp:LinkButton id="EditButton"
Text="Edit"
CommandName="Edit"
runat="server"/>
</ItemTemplate>
<EditItemTemplate>
Item:
<asp:Label id="ItemLabel"
Text='<%# DataBinder.Eval(Container.DataItem, "Item") %>'
runat="server"/>
<br />
Quantity:
<asp:TextBox id="QtyTextBox"
Text='<%# DataBinder.Eval(Container.DataItem, "Qty") %>'
runat="server"/>
<br />
Price:
<asp:TextBox id="PriceTextBox"
Text='<%# DataBinder.Eval(Container.DataItem, "Price", "{0:c}") %>'
runat="server"/>
<br />
<asp:LinkButton id="UpdateButton"
Text="Update"
CommandName="Update"
runat="server"/>
<asp:LinkButton id="DeleteButton"
Text="Delete"
CommandName="Delete"
runat="server"/>
<asp:LinkButton id="CancelButton"
Text="Cancel"
CommandName="Cancel"
runat="server"/>
</EditItemTemplate>
</asp:DataList>
</form>
</body>
</html>
<%@ Page Language="VB" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>DataList Edit Example</title>
<script runat="server">
' The Cart and CartView objects temporarily store the data source
' for the DataList control while the page is being processed.
Dim Cart As DataTable = New DataTable()
Dim CartView As DataView
Sub Page_Load(sende As Object, e As EventArgs)
' With a database, use an select query to retrieve the data.
' Because the data source in this example is an in-memory
' DataTable, retrieve the data from session state if it exists;
' otherwise, create the data source.
GetSource()
' The DataGrid control maintains state between posts to the server;
' it only needs to be bound to a data source the first time the
' page is loaded or when the data source is updated.
If Not IsPostBack Then
BindList()
End If
' Manually register the event-handling methods.
AddHandler ItemsList.EditCommand, AddressOf Edit_Command
AddHandler ItemsList.UpdateCommand, AddressOf Update_Command
AddHandler ItemsList.DeleteCommand, AddressOf Delete_Command
AddHandler ItemsList.CancelCommand, AddressOf Cancel_Command
End Sub
Sub BindList()
' Set the data source and bind to the DataList control.
ItemsList.DataSource = CartView
ItemsList.DataBind()
End Sub
Sub GetSource()
' For this example, the data source is a DataTable that
' is stored in session state. If the data source does not exist,
' create it; otherwise, load the data.
If Session("ShoppingCart") Is Nothing Then
' Create the sample data.
Dim dr As DataRow
' Define the columns of the table.
Cart.Columns.Add(new DataColumn("Qty", GetType(Int32)))
Cart.Columns.Add(new DataColumn("Item", GetType(String)))
Cart.Columns.Add(new DataColumn("Price", GetType(Double)))
' Store the table in session state to persist its values
' between posts to the server.
Session("ShoppingCart") = Cart
' Populate the DataTable with sample data.
Dim i As Integer
For i = 1 To 9
dr = Cart.NewRow()
If (i Mod 2) <> 0 Then
dr(0) = 2
Else
dr(0) = 1
End If
dr(1) = "Item " & i.ToString()
dr(2) = (1.23 * (i + 1))
Cart.Rows.Add(dr)
Next i
Else
' Retrieve the sample data from session state.
Cart = CType(Session("ShoppingCart"), DataTable)
End If
' Create a DataView and specify the field to sort by.
CartView = New DataView(Cart)
CartView.Sort="Item"
Return
End Sub
Sub Edit_Command(sender As Object, e As DataListCommandEventArgs)
' Set the EditItemIndex property to the index of the item clicked
' in the DataList control to enable editing for that item. Be sure
' to rebind the DataList to the data source to refresh the control.
ItemsList.EditItemIndex = e.Item.ItemIndex
BindList()
End Sub
Sub Cancel_Command(sender As Object, e As DataListCommandEventArgs)
' Set the EditItemIndex property to -1 to exit editing mode. Be sure
' to rebind the DataList to the data source to refresh the control.
ItemsList.EditItemIndex = -1
BindList()
End Sub
Sub Delete_Command(sender As Object, e As DataListCommandEventArgs)
' Retrieve the name of the item to remove.
Dim item As String = (CType(e.Item.FindControl("ItemLabel"), Label)).Text
' Filter the CartView for the selected item and remove it from
' the data source.
CartView.RowFilter = "Item='" & item & "'"
If CartView.Count > 0 Then
CartView.Delete(0)
End If
CartView.RowFilter = ""
' Set the EditItemIndex property to -1 to exit editing mode. Be sure
' to rebind the DataList to the data source to refresh the control.
ItemsList.EditItemIndex = -1
BindList()
End Sub
Sub Update_Command(sender As Object, e As DataListCommandEventArgs)
' Retrieve the updated values from the selected item.
Dim item As String = _
(CType(e.Item.FindControl("ItemLabel"), Label)).Text
Dim qty As String = _
(CType(e.Item.FindControl("QtyTextBox"), TextBox)).Text
Dim price As String = _
(CType(e.Item.FindControl("PriceTextBox"), TextBox)).Text
' With a database, use an update command to update the data.
' Because the data source in this example is an in-memory
' DataTable, delete the old row and replace it with a new one.
' Filter the CartView for the selected item and remove it from
' the data source.
CartView.RowFilter = "Item='" & item & "'"
If CartView.Count > 0 Then
CartView.Delete(0)
End If
CartView.RowFilter = ""
' ***************************************************************
' Insert data validation code here. Make sure to validate the
' values entered by the user before converting to the appropriate
' data types and updating the data source.
' ***************************************************************
' Add a new entry to replace the previous item.
Dim dr As DataRow = Cart.NewRow()
dr(0) = qty
dr(1) = item
' If necessary, remove the '$' character from the price before
' converting the price to a Double.
If price.Chars(0) = "$" Then
dr(2) = Convert.ToDouble(price.Substring(1))
Else
dr(2) = Convert.ToDouble(price)
End If
Cart.Rows.Add(dr)
' Set the EditItemIndex property to -1 to exit editing mode.
' Be sure to rebind the DataList to the data source to refresh
' the control.
ItemsList.EditItemIndex = -1
BindList()
End Sub
</script>
</head>
<body>
<form id="form1" runat="server">
<h3>DataList Edit Example</h3>
Click <b>Edit</b> to edit the values of the item.
<br /><br />
<asp:DataList id="ItemsList"
GridLines="Both"
RepeatColumns="3"
RepeatDirection="Horizontal"
CellPadding="3"
CellSpacing="0"
OnEditCommand="Edit_Command"
OnUpdateCommand="Update_Command"
OnDeleteCommand="Delete_Command"
OnCancelCommand="Cancel_Command"
runat="server">
<HeaderStyle BackColor="#aaaadd">
</HeaderStyle>
<AlternatingItemStyle BackColor="Gainsboro">
</AlternatingItemStyle>
<EditItemStyle BackColor="yellow">
</EditItemStyle>
<HeaderTemplate>
Items
</HeaderTemplate>
<ItemTemplate>
Item:
<%# DataBinder.Eval(Container.DataItem, "Item") %>
<br />
Quantity:
<%# DataBinder.Eval(Container.DataItem, "Qty") %>
<br />
Price:
<%# DataBinder.Eval(Container.DataItem, "Price", "{0:c}") %>
<br />
<asp:LinkButton id="EditButton"
Text="Edit"
CommandName="Edit"
runat="server"/>
</ItemTemplate>
<EditItemTemplate>
Item:
<asp:Label id="ItemLabel"
Text='<%# DataBinder.Eval(Container.DataItem, "Item") %>'
runat="server"/>
<br />
Quantity:
<asp:TextBox id="QtyTextBox"
Text='<%# DataBinder.Eval(Container.DataItem, "Qty") %>'
runat="server"/>
<br />
Price:
<asp:TextBox id="PriceTextBox"
Text='<%# DataBinder.Eval(Container.DataItem, "Price", "{0:c}") %>'
runat="server"/>
<br />
<asp:LinkButton id="UpdateButton"
Text="Update"
CommandName="Update"
runat="server"/>
<asp:LinkButton id="DeleteButton"
Text="Delete"
CommandName="Delete"
runat="server"/>
<asp:LinkButton id="CancelButton"
Text="Cancel"
CommandName="Cancel"
runat="server"/>
</EditItemTemplate>
</asp:DataList>
</form>
</body>
</html>
Hinweise
Das CancelCommand Ereignis wird ausgelöst, wenn auf die Cancel
Schaltfläche für ein Element im DataList Steuerelement geklickt wird.
Ein typischer Handler für das CancelCommand -Ereignis legt die EditItemIndex -Eigenschaft auf fest -1
(um die Auswahl des Elements aufzuheben) und die Daten dann erneut an das DataList Steuerelement zu binden.
Achtung
Text ist nicht HTML-codiert, bevor er im DataList -Steuerelement angezeigt wird. Dies ermöglicht das Einbetten von Skripts in HTML-Tags in den Text. Wenn die Werte für das Steuerelement aus Benutzereingaben stammen, überprüfen Sie die Werte, um Sicherheitsrisiken zu verringern.
Weitere Informationen zum Behandeln von Ereignissen finden Sie unter Vorgehensweise: Nutzen von Ereignissen in einer Web Forms-Anwendung.
Achtung
Dieses Steuerelement kann verwendet werden, um Benutzereingaben anzuzeigen, die möglicherweise böswillige Clientskripts enthalten. Überprüfen Sie alle Informationen, die von einem Client auf ausführbare Skripts, SQL-Anweisungen oder anderen Code gesendet werden, bevor Sie sie in Ihrer Anwendung anzeigen. Sie können Validierungssteuerelemente verwenden, um die Benutzereingabe zu überprüfen, bevor der Eingabetext in einem Steuerelement angezeigt wird. ASP.NET stellt eine Überprüfungsfunktion für Eingabeanforderungen bereit, um Skripts und HTML in Benutzereingaben zu blockieren. Weitere Informationen finden Sie unter Sichern von Standardsteuerelementen, Vorgehensweise: Schützen vor Skript-Exploits in einer Webanwendung durch Anwenden von HTML-Codierung auf Zeichenfolgen und Überprüfen von Benutzereingaben in ASP.NET Webseiten.
Gilt für:
Weitere Informationen
- DataListCommandEventHandler
- OnCancelCommand(DataListCommandEventArgs)
- DeleteCommand
- EditCommand
- UpdateCommand
- Sichern von Standardsteuerelementen
- Vorgehensweise: Schutz vor Skript-Exploits in einer Webanwendung durch Anwenden der HTML-Codierung auf Zeichenfolgen
- Einführung in das Überprüfen von Benutzereingaben in ASP.NET Webseiten
- ASP.NET Webseitencodemodell