FormView.DataItem Özellik
Tanım
Önemli
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Denetime bağlı FormView veri öğesini alır.
public:
virtual property System::Object ^ DataItem { System::Object ^ get(); };[System.ComponentModel.Browsable(false)]
public virtual object DataItem { get; }[<System.ComponentModel.Browsable(false)>]
member this.DataItem : objPublic Overridable ReadOnly Property DataItem As ObjectÖzellik Değeri
Object Denetime bağlı FormView veri öğesini temsil eden bir.
Uygulamalar
- Öznitelikler
Örnekler
Aşağıdaki örnekte, veri öğesindeki DataItem bir alanın değerini belirlemek için özelliğinin nasıl kullanılacağı gösterilmektedir.
<%@ page language="C#" %>
<%@ import namespace="System.Data"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
// To dynamically create a template for a FormView control,
// you must create a custom template class to represent
// the template. This template class represents the item
// template for a FormView control.
private sealed class EmployeeTemplate : ITemplate
{
// When implementing the ITemplate interface, you must
// implement the InstantiateIn method. The FormView
// control calls this method to create the template's
// content.
void ITemplate.InstantiateIn(Control container)
{
// Create the child controls contained in the template.
// For this example, the item template displays the
// FirstName and LastName fields from the data source.
// To support data binding, create event handlers
// for the DataBinding event of each child child control.
// The event handler must bind the appropriate value
// to the control.
Label firstNameLabel = new Label();
firstNameLabel.ID = "FirstNameLabel";
firstNameLabel.DataBinding += new EventHandler(FirstNameLabel_DataBinding);
LiteralControl lineBreak = new LiteralControl("<br/>");
Label lastNameLabel = new Label();
lastNameLabel.ID = "LastNameLabel";
lastNameLabel.DataBinding += new EventHandler(LastNameLabel_DataBinding);
// Add the controls to the Controls collection of the
// container control.
container.Controls.Add(firstNameLabel);
container.Controls.Add(lineBreak);
container.Controls.Add(lastNameLabel);
}
// This event handler binds the value of the FirstName field
// to the FirstNameLabel Label control displayed in the template.
private void FirstNameLabel_DataBinding(Object sender, EventArgs e)
{
// Use the sender parameter to retrieve the Label control
// being bound to data.
Label firstNameLabelControl = (Label)sender;
// Retrieve the value to bind to the Label control. First,
// use the NamingContainer property to retrieve the parent
// control of the Label control. In this example, the parent
// control is the FormView control.
FormView formViewContainer = (FormView)firstNameLabelControl.NamingContainer;
// Get the data item bound to the FormView control.
DataRowView rowView = (DataRowView)formViewContainer.DataItem;
// Use the data item to retrieve the value of the FirstName field
// Set the Text property of the Label control to this value.
firstNameLabelControl.Text = rowView["FirstName"].ToString();
}
// This event handler binds the value of the LastName field
// to the LastNameLabel Label control displayed in the template.
private void LastNameLabel_DataBinding(Object sender, EventArgs e)
{
// Use the sender parameter to retrieve the Label control
// being bound to data.
Label lastNameLabelControl = (Label)sender;
// Retrieve the value to bind to the Label control. First,
// use the NamingContainer property to retrieve the parent
// control of the Label control. In this example, the parent
// control is the FormView control.
FormView formViewContainer = (FormView)lastNameLabelControl.NamingContainer;
// Get the data item bound to the FormView control.
DataRowView rowView = (DataRowView)formViewContainer.DataItem;
// Use the data item to retrieve the value of the LastName field.
// Set the Text property of the Label control to this value.
lastNameLabelControl.Text = rowView["LastName"].ToString();
}
}
void Page_Load(Object sender, EventArgs e)
{
// Create a new FormView object.
FormView employeesFormView = new FormView();
// Set the FormView object's properties.
employeesFormView.ID = "EmployeesFormView";
employeesFormView.DataSourceID = "EmployeeSource";
employeesFormView.AllowPaging = true;
employeesFormView.PagerSettings.Mode = PagerButtons.NextPrevious;
employeesFormView.HeaderText = "Employee Name";
employeesFormView.RowStyle.BackColor = System.Drawing.Color.LightBlue;
employeesFormView.HeaderStyle.BackColor = System.Drawing.Color.Silver;
employeesFormView.PagerStyle.BackColor = System.Drawing.Color.Silver;
// Create the dynamic template using the custom template class.
employeesFormView.ItemTemplate = new EmployeeTemplate();
// Add the FormView object to the Controls collection
// of the PlaceHolder control.
DetailsViewPlaceHolder.Controls.Add(employeesFormView);
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>FormView Constructor Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>FormView Constructor Example</h3>
<!-- Use a PlaceHolder control as the container for the -->
<!-- dynamically generated FormView control. -->
<asp:PlaceHolder id="DetailsViewPlaceHolder"
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] From [Employees]"
connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
runat="server"/>
</form>
</body>
</html>
<%@ page language="VB" %>
<%@ import namespace="System.Data"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
' To dynamically create a template for a FormView control,
' you must create a custom template class to represent
' the template. This template class represents the item
' template for a FormView control.
Private NotInheritable Class EmployeeTemplate
Implements ITemplate
' When implementing the ITemplate interface, you must
' implement the InstantiateIn method. The FormView
' control calls this method to create the template's
' content.
Sub InstantiateIn(ByVal container As Control) Implements ITemplate.InstantiateIn
' Create the child controls contained in the template.
' For this example, the item template displays the
' FirstName and LastName fields from the data source.
' To support data binding, create event handlers
' for the DataBinding event of each child child control.
' The event handler must bind the appropriate value
' to the control.
Dim firstNameLabel As New Label()
firstNameLabel.ID = "FirstNameLabel"
AddHandler firstNameLabel.DataBinding, AddressOf FirstNameLabel_DataBinding
Dim lineBreak As LiteralControl = New LiteralControl("<br/>")
Dim lastNameLabel As New Label()
lastNameLabel.ID = "LastNameLabel"
AddHandler lastNameLabel.DataBinding, AddressOf LastNameLabel_DataBinding
' Add the controls to the Controls collection of the
' container control.
container.Controls.Add(firstNameLabel)
container.Controls.Add(lineBreak)
container.Controls.Add(lastNameLabel)
End Sub
' This event handler binds the value of the FirstName field
' to the FirstNameLabel Label control displayed in the template.
Private Sub FirstNameLabel_DataBinding(ByVal sender As Object, ByVal e As EventArgs)
' Use the sender parameter to retrieve the Label control
' being bound to data.
Dim firstNameLabelControl As Label = CType(sender, Label)
' Retrieve the value to bind to the Label control. First,
' use the NamingContainer property to retrieve the parent
' control of the Label control. In this example, the parent
' control is the FormView control.
Dim formViewContainer As FormView = CType(firstNameLabelControl.NamingContainer, FormView)
' Get the data item bound to the FormView control.
Dim rowView As DataRowView = CType(formViewContainer.DataItem, DataRowView)
' Use the data item to retrieve the value of the FirstName field
' Set the Text property of the Label control to this value.
firstNameLabelControl.Text = rowView("FirstName").ToString()
End Sub
' This event handler binds the value of the LastName field
' to the LastNameLabel Label control displayed in the template.
Private Sub LastNameLabel_DataBinding(ByVal sender As Object, ByVal e As EventArgs)
' Use the sender parameter to retrieve the Label control
' being bound to data.
Dim lastNameLabelControl As Label = CType(sender, Label)
' Retrieve the value to bind to the Label control. First,
' use the NamingContainer property to retrieve the parent
' control of the Label control. In this example, the parent
' control is the FormView control.
Dim formViewContainer As FormView = CType(lastNameLabelControl.NamingContainer, FormView)
' Get the data item bound to the FormView control.
Dim rowView As DataRowView = CType(formViewContainer.DataItem, DataRowView)
' Use the data item to retrieve the value of the LastName field
' Set the Text property of the Label control to this value.
lastNameLabelControl.Text = rowView("LastName").ToString()
End Sub
End Class
Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
' Create a new FormView object.
Dim employeesFormView As New FormView()
' Set the FormView object's properties.
employeesFormView.ID = "EmployeesFormView"
employeesFormView.DataSourceID = "EmployeeSource"
employeesFormView.AllowPaging = True
employeesFormView.PagerSettings.Mode = PagerButtons.NextPrevious
employeesFormView.HeaderText = "Employee Name"
employeesFormView.RowStyle.BackColor = System.Drawing.Color.LightBlue
employeesFormView.HeaderStyle.BackColor = System.Drawing.Color.Silver
employeesFormView.PagerStyle.BackColor = System.Drawing.Color.Silver
' Create the dynamic template using the custom template class.
employeesFormView.ItemTemplate = New EmployeeTemplate()
' Add the FormView object to the Controls collection
' of the PlaceHolder control.
DetailsViewPlaceHolder.Controls.Add(employeesFormView)
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>FormView Constructor Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>FormView Constructor Example</h3>
<!-- Use a PlaceHolder control as the container for the -->
<!-- dynamically generated FormView control. -->
<asp:PlaceHolder id="DetailsViewPlaceHolder"
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] From [Employees]"
connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
runat="server"/>
</form>
</body>
</html>
Açıklamalar
Denetimine DataItem bağlı veri öğesine erişmek için FormView özelliğini kullanın. Veri öğesi genellikle geçerli kaydın alan değerlerine doğrudan erişmek için kullanılır. Bu özellik tarafından döndürülen türü Object veri kaynağına bağlı olarak değişir. Örneğin, denetim SqlDataSource denetime FormView bağlı olduğunda bir DataRowView nesne döndürülür.
Not
Bu özellik yalnızca veri bağlama gerçekleştikten sonra kullanılabilir. Veri bağlama gerçekleşmeden önce bu özellik döndürür null. Bu özellik, denetim ekleme modundayken ve döndürdüğünde FormView nullde geçerli değildir.