FormViewUpdateEventArgs.Keys Vlastnost
Definice
Důležité
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Získá slovník, který obsahuje původní klíč pole název/hodnota páry pro záznam k aktualizaci.
public:
property System::Collections::Specialized::IOrderedDictionary ^ Keys { System::Collections::Specialized::IOrderedDictionary ^ get(); };public System.Collections.Specialized.IOrderedDictionary Keys { get; }member this.Keys : System.Collections.Specialized.IOrderedDictionaryPublic ReadOnly Property Keys As IOrderedDictionaryHodnota vlastnosti
Obsahuje IOrderedDictionary slovník dvojic název/hodnota původního pole klíče pro aktualizaci záznamu.
Příklady
Následující příklad ukazuje, jak použít Keys vlastnost pro přístup k hodnotě pole klíče pro aktualizovaný záznam.
<%@ Page language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
void EmployeeFormView_ItemUpdating(Object sender, FormViewUpdateEventArgs e)
{
// Validate the field values entered by the user. This
// example determines whether the user left any fields
// empty. The names of the empty fields are added to
// an ArrayList object.
// Use the NewValues property to access the new
// values entered by the user.
ArrayList emptyFieldList = ValidateFields((OrderedDictionary)e.NewValues);
if (emptyFieldList.Count > 0)
{
// The user left some fields empty. Display an error message.
// Use the Keys property to retrieve the key field value.
String keyValue = e.Keys["EmployeeID"].ToString();
MessageLabel.Text = "You must enter a value for each field of record " +
keyValue + ".<br/>The following fields are missing:<br/><br/>";
// Display the missing fields.
foreach (String value in emptyFieldList)
{
// Use the OldValues property to access the original value
// of a field.
MessageLabel.Text += value + " - Original Value = " +
e.OldValues[value].ToString() + "<br />";
}
// Cancel the update operation.
e.Cancel = true;
}
else
{
// The field values passed validation. Clear the
// error message label.
MessageLabel.Text = "";
}
}
ArrayList ValidateFields(OrderedDictionary list)
{
// Create an ArrayList object to store the
// names of any empty fields.
ArrayList emptyFieldList = new ArrayList();
// Iterate though the field values entered by
// the user and check for an empty field.
foreach (DictionaryEntry entry in list)
{
if (entry.Value.Equals(""))
{
// Add the field name to the ArrayList object.
emptyFieldList.Add(entry.Key.ToString());
}
}
return emptyFieldList;
}
void EmployeeFormView_ModeChanged(Object sender, EventArgs e)
{
// Clear the error message label.
MessageLabel.Text = "";
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>FormViewUpdateEventArgs Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>FormViewUpdateEventArgs Example</h3>
<asp:formview id="EmployeeFormView"
datasourceid="EmployeeSource"
allowpaging="true"
datakeynames="EmployeeID"
emptydatatext="No employees found."
onitemupdating="EmployeeFormView_ItemUpdating"
onmodechanged="EmployeeFormView_ModeChanged"
runat="server">
<itemtemplate>
<table>
<tr>
<td rowspan="6">
<asp:image id="EmployeeImage"
imageurl='<%# Eval("PhotoPath") %>'
alternatetext='<%# Eval("LastName") %>'
runat="server"/>
</td>
<td colspan="2">
</td>
</tr>
<tr>
<td>
<b>Name:</b>
</td>
<td>
<%# Eval("FirstName") %> <%# Eval("LastName") %>
</td>
</tr>
<tr>
<td>
<b>Title:</b>
</td>
<td>
<%# Eval("Title") %>
</td>
</tr>
<tr style="height:150" valign="top">
<td>
<b>Address:</b>
</td>
<td>
<%# Eval("Address") %><br/>
<%# Eval("City") %> <%# Eval("Region") %>
<%# Eval("PostalCode") %><br/>
<%# Eval("Country") %>
</td>
</tr>
<tr>
<td colspan="2">
<asp:linkbutton id="Edit"
text="Edit"
commandname="Edit"
runat="server"/>
</td>
</tr>
</table>
</itemtemplate>
<edititemtemplate>
<table>
<tr>
<td rowspan="6">
<asp:image id="EmployeeEditImage"
imageurl='<%# Eval("PhotoPath") %>'
alternatetext='<%# Eval("LastName") %>'
runat="server"/>
</td>
<td colspan="2">
</td>
</tr>
<tr>
<td>
<b><asp:Label runat="server"
AssociatedControlID="FirstNameUpdateTextBox"
Text="Name" />:</b>
</td>
<td>
<asp:textbox id="FirstNameUpdateTextBox"
text='<%# Bind("FirstName") %>'
accesskey="n" tabindex="1" runat="server"/>
<asp:textbox id="LastNameUpdateTextBox"
text='<%# Bind("LastName") %>'
accesskey="l" tabindex="2" runat="server"/>
</td>
</tr>
<tr>
<td>
<b><asp:Label runat="server"
AssociatedControlID="TitleUpdateTextBox"
Text="Title" />:</b>
</td>
<td>
<asp:textbox id="TitleUpdateTextBox"
text='<%# Bind("Title") %>'
accesskey="t" tabindex="3" runat="server"/>
</td>
</tr>
<tr>
<b><asp:Label runat="server"
AssociatedControlID="HireDateUpdateTextBox"
Text="Hire Date" />:</b>
<td>
<asp:textbox id="HireDateUpdateTextBox"
text='<%# Bind("HireDate", "{0:d}") %>'
accesskey="h" tabindex="4" runat="server" />
</td>
</tr>
<tr style="height:150" valign="top">
<td>
<b><asp:Label runat="server"
AssociatedControlID="AddressUpdateTextBox"
Text="Address" />:</b>
</td>
<td>
<asp:textbox id="AddressUpdateTextBox"
text='<%# Bind("Address") %>'
accesskey="a" tabindex="5" runat="server"/>
<br/>
<asp:textbox id="CityUpdateTextBox"
text='<%# Bind("City") %>'
accesskey="c" tabindex="6" runat="server"/>
<asp:textbox id="RegionUpdateTextBox"
text='<%# Bind("Region") %>'
width="40"
accesskey="r" tabindex="7" runat="server"/>
<asp:textbox id="PostalCodeUpdateTextBox"
text='<%# Bind("PostalCode") %>'
width="60"
accesskey="p" tabindex="8" runat="server"/>
<br/>
<asp:textbox id="CountryUpdateTextBox"
text='<%# Bind("Country") %>'
accesskey="u" tabindex="9" runat="server"/>
</td>
</tr>
<tr>
<td colspan="2">
<asp:linkbutton id="UpdateButton"
text="Update" tabindex="10"
commandname="Update"
runat="server"/>
<asp:linkbutton id="CancelButton"
text="Cancel" tabindex="11"
commandname="Cancel"
runat="server"/>
</td>
</tr>
</table>
</edititemtemplate>
</asp:formview>
<br/><br/>
<asp:label id="MessageLabel"
forecolor="Red"
runat="server"/>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the Northwind sample database. Use an ASP.NET -->
<!-- expression to retrieve the connection string value -->
<!-- from the Web.config file. -->
<asp:sqldatasource id="EmployeeSource"
selectcommand="Select [EmployeeID], [LastName], [FirstName], [Title], [Address], [City], [Region], [PostalCode], [Country], [HireDate], [PhotoPath] From [Employees]"
updatecommand="Update [Employees] Set [LastName]=@LastName, [FirstName]=@FirstName, [Title]=@Title, [Address]=@Address, [City]=@City, [Region]=@Region, [PostalCode]=@PostalCode, [Country]=@Country Where [EmployeeID]=@EmployeeID"
connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
runat="server"/>
</form>
</body>
</html>
<%@ Page language="VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
Sub EmployeeFormView_ItemUpdating(ByVal sender As Object, ByVal e As FormViewUpdateEventArgs) Handles EmployeeFormView.ItemUpdating
' Validate the field values entered by the user. This
' example determines whether the user left any fields
' empty. The names of the empty fields are added to
' an ArrayList object.
' Use the NewValues property to access the new
' values entered by the user.
Dim emptyFieldList As ArrayList = ValidateFields(CType(e.NewValues, OrderedDictionary))
If emptyFieldList.Count > 0 Then
' The user left some fields empty. Display an error message.
' Use the Keys property to retrieve the key field value.
Dim keyValue As String = e.Keys("EmployeeID").ToString()
MessageLabel.Text = "You must enter a value for each field of record " & _
keyValue & ".<br/>The following fields are missing:<br/><br/>"
' Display the missing fields.
Dim value As String
For Each value In emptyFieldList
' Use the OldValues property access the original value
' of a field.
MessageLabel.Text &= value & " - Original Value = " & _
e.OldValues(value).ToString() & "<br />"
Next
' Cancel the update operation.
e.Cancel = True
Else
' The field values passed validation. Clear the
' error message label.
MessageLabel.Text = ""
End If
End Sub
Function ValidateFields(ByVal list As OrderedDictionary) As ArrayList
' Create an ArrayList object to store the
' names of any empty fields.
Dim emptyFieldList As New ArrayList()
' Iterate though the field values entered by
' the user and check for an empty field.
Dim entry As DictionaryEntry
For Each entry In list
If entry.Value.Equals("") Then
' Add the field name to the ArrayList object.
emptyFieldList.Add(entry.Key.ToString())
End If
Next
Return emptyFieldList
End Function
Sub EmployeeFormView_ModeChanged(ByVal sender As Object, ByVal e As EventArgs) Handles EmployeeFormView.ModeChanged
' Clear the error message label.
MessageLabel.Text = ""
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>FormViewUpdateEventArgs Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>FormViewUpdateEventArgs Example</h3>
<asp:formview id="EmployeeFormView"
datasourceid="EmployeeSource"
allowpaging="true"
datakeynames="EmployeeID"
emptydatatext="No employees found."
runat="server">
<itemtemplate>
<table>
<tr>
<td rowspan="6">
<asp:image id="EmployeeImage"
imageurl='<%# Eval("PhotoPath") %>'
alternatetext='<%# Eval("LastName") %>'
runat="server"/>
</td>
<td colspan="2">
</td>
</tr>
<tr>
<td>
<b>Name:</b>
</td>
<td>
<%# Eval("FirstName") %> <%# Eval("LastName") %>
</td>
</tr>
<tr>
<td>
<b>Title:</b>
</td>
<td>
<%# Eval("Title") %>
</td>
</tr>
<tr style="height:150" valign="top">
<td>
<b>Address:</b>
</td>
<td>
<%# Eval("Address") %><br/>
<%# Eval("City") %> <%# Eval("Region") %>
<%# Eval("PostalCode") %><br/>
<%# Eval("Country") %>
</td>
</tr>
<tr>
<td colspan="2">
<asp:linkbutton id="Edit"
text="Edit"
commandname="Edit"
runat="server"/>
</td>
</tr>
</table>
</itemtemplate>
<edititemtemplate>
<table>
<tr>
<td rowspan="6">
<asp:image id="EmployeeEditImage"
imageurl='<%# Eval("PhotoPath") %>'
alternatetext='<%# Eval("LastName") %>'
runat="server"/>
</td>
<td colspan="2">
</td>
</tr>
<tr>
<td>
<b><asp:Label runat="server"
AssociatedControlID="FirstNameUpdateTextBox"
Text="Name" />:</b>
</td>
<td>
<asp:textbox id="FirstNameUpdateTextBox"
text='<%# Bind("FirstName") %>'
accesskey="n" tabindex="1" runat="server"/>
<asp:textbox id="LastNameUpdateTextBox"
text='<%# Bind("LastName") %>'
accesskey="l" tabindex="2" runat="server"/>
</td>
</tr>
<tr>
<td>
<b><asp:Label runat="server"
AssociatedControlID="TitleUpdateTextBox"
Text="Title" />:</b>
</td>
<td>
<asp:textbox id="TitleUpdateTextBox"
text='<%# Bind("Title") %>'
accesskey="t" tabindex="3" runat="server"/>
</td>
</tr>
<tr>
<b><asp:Label runat="server"
AssociatedControlID="HireDateUpdateTextBox"
Text="Hire Date" />:</b>
<td>
<asp:textbox id="HireDateUpdateTextBox"
text='<%# Bind("HireDate", "{0:d}") %>'
accesskey="h" tabindex="4" runat="server" />
</td>
</tr>
<tr style="height:150" valign="top">
<td>
<b><asp:Label runat="server"
AssociatedControlID="AddressUpdateTextBox"
Text="Address" />:</b>
</td>
<td>
<asp:textbox id="AddressUpdateTextBox"
text='<%# Bind("Address") %>'
accesskey="a" tabindex="5" runat="server"/>
<br/>
<asp:textbox id="CityUpdateTextBox"
text='<%# Bind("City") %>'
accesskey="c" tabindex="6" runat="server"/>
<asp:textbox id="RegionUpdateTextBox"
text='<%# Bind("Region") %>'
width="40"
accesskey="r" tabindex="7" runat="server"/>
<asp:textbox id="PostalCodeUpdateTextBox"
text='<%# Bind("PostalCode") %>'
width="60"
accesskey="p" tabindex="8" runat="server"/>
<br/>
<asp:textbox id="CountryUpdateTextBox"
text='<%# Bind("Country") %>'
accesskey="u" tabindex="9" runat="server"/>
</td>
</tr>
<tr>
<td colspan="2">
<asp:linkbutton id="UpdateButton"
text="Update" tabindex="10"
commandname="Update"
runat="server"/>
<asp:linkbutton id="CancelButton"
text="Cancel" tabindex="11"
commandname="Cancel"
runat="server"/>
</td>
</tr>
</table>
</edititemtemplate>
</asp:formview>
<br/><br/>
<asp:label id="MessageLabel"
forecolor="Red"
runat="server"/>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the Northwind sample database. Use an ASP.NET -->
<!-- expression to retrieve the connection string value -->
<!-- from the Web.config file. -->
<asp:sqldatasource id="EmployeeSource"
selectcommand="Select [EmployeeID], [LastName], [FirstName], [Title], [Address], [City], [Region], [PostalCode], [Country], [HireDate], [PhotoPath] From [Employees]"
updatecommand="Update [Employees] Set [LastName]=@LastName, [FirstName]=@FirstName, [Title]=@Title, [Address]=@Address, [City]=@City, [Region]=@Region, [PostalCode]=@PostalCode, [Country]=@Country Where [EmployeeID]=@EmployeeID"
connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
runat="server"/>
</form>
</body>
</html>
Poznámky
Vlastnost Keys obsahuje původní hodnoty polí klíčů uvedených ve DataKeyNames vlastnosti ovládacího prvku FormView . Keys Pomocí vlastnosti můžete získat přístup k původním hodnotám polí klíčů, aby se záznam aktualizoval. Tyto hodnoty můžete použít například k uchování protokolu aktualizovaných záznamů.
Poznámka
Pokud uživateli povolíte aktualizovat hodnoty polí s klíči Keys , vlastnost obsahuje hodnoty původního pole klíče. Aktualizované hodnoty jsou uloženy ve NewValues vlastnosti.
Vlastnost Keys vrátí OrderedDictionary objekt, který implementuje System.Collections.Specialized.IOrderedDictionary rozhraní. Objekt OrderedDictionary obsahuje System.Collections.DictionaryEntry objekty, které představují pole aktualizovaného záznamu. Pro přístup k názvům polí použijte Keys vlastnost objektu OrderedDictionary . Podobně můžete k hodnotám polí přistupovat pomocí Values vlastnosti .
Poznámka
Jako zástupce můžete také použít indexer objektu OrderedDictionary pro přímý přístup k hodnotám polí. Ovládací prvky zdroje dat, které se spoléhají na pořadí polí (například AccessDataSource), mají přístup k hodnotám polí pouze podle indexu.
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