DataListCommandEventHandler Delegát
Definice
Důležité
Některé informace platí pro předběžně vydaný produkt, který se může zásadně změnit, než ho výrobce nebo autor vydá. Microsoft neposkytuje žádné záruky, výslovné ani předpokládané, týkající se zde uváděných informací.
Představuje metodu, která bude zpracovávat CancelCommand, DeleteCommand, EditCommand, ItemCommanda UpdateCommand události DataList ovládacího prvku.
public delegate void DataListCommandEventHandler(System::Object ^ source, DataListCommandEventArgs ^ e);public delegate void DataListCommandEventHandler(object source, DataListCommandEventArgs e);type DataListCommandEventHandler = delegate of obj * DataListCommandEventArgs -> unitPublic Delegate Sub DataListCommandEventHandler(source As Object, e As DataListCommandEventArgs)Parametry
- source
- Object
Zdroj události
A DataListCommandEventArgs obsahující data události.
Příklady
Následující příklad ukazuje, jak definovat obslužné rutiny událostí pro EditCommand, UpdateCommandCancelCommanda DeleteCommand události DataList ovládacího prvku. Tento příklad určuje obslužné rutiny událostí deklarativní, nastavení obslužné rutiny události pro každou vlastnost příkazu v ovládacím DataList prvku.
<%@ 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>
Následující příklad kódu ukazuje, jak určit obslužné rutiny událostí a programově přidat do událostí v Page_Load metodě.
<%@ 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>
Poznámky
Událost CancelCommand se vyvolá při kliknutí na Cancel tlačítko položky v ovládacím DataList prvku.
Událost DeleteCommand se vyvolá při kliknutí na Delete tlačítko položky v ovládacím DataList prvku.
Událost EditCommand se vyvolá při kliknutí na Edit tlačítko položky v ovládacím DataList prvku.
Událost ItemCommand se vyvolá, když kliknete na libovolné tlačítko položky v ovládacím DataList prvku. To vám umožní programově testovat, kdy se na konkrétní příkazové tlačítko klikne a provede příslušnou akci. Tato událost se běžně používá ke zpracování vlastních příkazových tlačítek pro DataList ovládací prvek.
Událost UpdateCommand se vyvolá při kliknutí na Update tlačítko položky v ovládacím DataList prvku.
Při vytváření delegáta DataListCommandEventHandler identifikujete metodu, která bude zpracovávat událost. Pokud chcete událost přidružit k obslužné rutině události, přidejte do události instanci delegáta. Obslužná rutina události se volá při každém výskytu události, pokud delegáta neodeberete. Další informace o delegátech obslužné rutiny událostí naleznete v tématu Zpracování a vyvolávání událostí.
Metody rozšíření
| Name | Description |
|---|---|
| GetMethodInfo(Delegate) |
Získá objekt, který představuje metodu reprezentovanou zadaným delegátem. |
