DataBinding Kelas
Definisi
Penting
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Berisi informasi tentang ekspresi pengikatan data tunggal dalam kontrol server ASP.NET, yang memungkinkan perancang pengembangan aplikasi cepat (RAD), seperti Microsoft Visual Studio, untuk membuat ekspresi pengikatan data pada waktu desain. Kelas ini tidak dapat diwariskan.
public ref class DataBinding sealedpublic sealed class DataBindingtype DataBinding = classPublic NotInheritable Class DataBinding- Warisan
-
DataBinding
Contoh
Contoh kode berikut membuat DataBinding objek dan mengaturnya sama dengan objek yang ada dalam koleksi kontrol DataBindingCollection yang memiliki propertyName parameter dengan nilai Text. Jika koleksi berisi DataBinding objek dengan propertyName nilai Text, kode ini mengembalikan nilai properti objek Expression . Jika tidak ada objek seperti itu, maka akan mengembalikan string kosong ("").
// Create the custom class that accesses the DataBinding and
// DataBindingCollection classes at design time.
public class SimpleDesigner : System.Web.UI.Design.ControlDesigner
{
// Create a Text property with accessors that obtain
// the property value from and set the property value
// to the Text key in the DataBindingCollection class.
public string Text
{
get
{
DataBinding myBinding = DataBindings["Text"];
if (myBinding != null)
{
return myBinding.Expression;
}
return String.Empty;
}
set
{
if ((value == null) || (value.Length == 0))
{
DataBindings.Remove("Text");
}
else
{
DataBinding binding = DataBindings["Text"];
if (binding == null)
{
binding = new DataBinding("Text", typeof(string), value);
}
else
{
binding.Expression = value;
}
// Call the DataBinding constructor, then add
// the initialized DataBinding object to the
// DataBindingCollection for this custom designer.
DataBinding binding1 = (DataBinding)DataBindings.SyncRoot;
DataBindings.Add(binding);
DataBindings.Add(binding1);
}
PropertyChanged("Text");
}
}
protected void PropertyChanged(string propName)
{
IControlDesignerTag myHtmlControlDesignBehavior = this.Tag;
DataBindingCollection myDataBindingCollection;
DataBinding myDataBinding1, myDataBinding2;
String myStringReplace1, myDataBindingExpression1, removedBinding, removedBindingAfterReplace, myDataBindingExpression2, myStringReplace2;
string[] removedBindings1, removedBindings2;
Int32 temp;
if (myHtmlControlDesignBehavior == null)
return;
// Use the DataBindingCollection constructor to
// create the myDataBindingCollection1 object.
// Then set this object equal to the
// DataBindings property of the control created
// by this custom designer.
DataBindingCollection myDataBindingCollection1 = new DataBindingCollection();
myDataBindingCollection1 = myDataBindingCollection = DataBindings;
if (myDataBindingCollection.Contains(propName))
{
myDataBinding1 = myDataBindingCollection[propName];
myStringReplace1 = propName.Replace(".", "-");
if (myDataBinding1 == null)
{
myHtmlControlDesignBehavior.RemoveAttribute(myStringReplace1);
return;
}
// DataBinding is not null.
myDataBindingExpression1 = String.Concat("<%#", myDataBinding1.Expression, "%>");
myHtmlControlDesignBehavior.SetAttribute(myStringReplace1, myDataBindingExpression1);
int index = myStringReplace1.IndexOf("-");
}
else
{
// Use the DataBindingCollection.RemovedBindings
// property to set the value of the removedBindings
// arrays.
removedBindings2 = removedBindings1 = DataBindings.RemovedBindings;
temp = 0;
while (removedBindings2.Length > temp)
{
removedBinding = removedBindings2[temp];
removedBindingAfterReplace = removedBinding.Replace('.', '-');
myHtmlControlDesignBehavior.RemoveAttribute(removedBindingAfterReplace);
temp = temp + 1;
}
}
// Use the DataBindingCollection.GetEnumerator method
// to iterate through the myDataBindingCollection object
// and write the PropertyName, PropertyType, and Expression
// properties to a file for each DataBinding object
// in the MyDataBindingCollection object.
myDataBindingCollection = DataBindings;
IEnumerator myEnumerator = myDataBindingCollection.GetEnumerator();
while (myEnumerator.MoveNext())
{
myDataBinding2 = (DataBinding)myEnumerator.Current;
String dataBindingOutput1, dataBindingOutput2, dataBindingOutput3;
dataBindingOutput1 = String.Concat("The property name is ", myDataBinding2.PropertyName);
dataBindingOutput2 = String.Concat("The property type is ", myDataBinding2.PropertyType.ToString(), "-", dataBindingOutput1);
dataBindingOutput3 = String.Concat("The expression is ", myDataBinding2.Expression, "-", dataBindingOutput2);
WriteToFile(dataBindingOutput3);
myDataBindingExpression2 = String.Concat("<%#", myDataBinding2.Expression, "%>");
myStringReplace2 = myDataBinding2.PropertyName.Replace(".", "-");
myHtmlControlDesignBehavior.SetAttribute(myStringReplace2, myDataBindingExpression2);
int index = myStringReplace2.IndexOf('-');
}// while loop ends
}
public void WriteToFile(string input)
{
// The WriteToFile custom method writes
// the values of the DataBinding properties
// to a file on the C drive at design time.
StreamWriter myFile = File.AppendText("C:\\DataBindingOutput.txt");
ASCIIEncoding encoder = new ASCIIEncoding();
byte[] ByteArray = encoder.GetBytes(input);
char[] CharArray = encoder.GetChars(ByteArray);
myFile.WriteLine(CharArray, 0, input.Length);
myFile.Close();
}
}
' Create the custom class that accesses the DataBinding and
' DataBindingCollection classes at design time.
Public Class SimpleDesigner
Inherits System.Web.UI.Design.ControlDesigner
' Create a Text property with accessors that obtain
' the property value from and set the property value
' to the Text key in the DataBindingCollection class.
Public Property [Text]() As String
Get
Dim myBinding As DataBinding = DataBindings("Text")
If Not (myBinding Is Nothing) Then
Return myBinding.Expression
End If
Return String.Empty
End Get
Set(ByVal value As String)
If value Is Nothing OrElse value.Length = 0 Then
DataBindings.Remove("Text")
Else
Dim binding As DataBinding = DataBindings("Text")
If binding Is Nothing Then
binding = New DataBinding("Text", GetType(String), value)
Else
binding.Expression = value
End If
' Call the DataBinding constructor, then add
' the initialized DataBinding object to the
' DataBindingCollection for this custom designer.
Dim binding1 As DataBinding = CType(DataBindings.SyncRoot, DataBinding)
DataBindings.Add(binding)
DataBindings.Add(binding1)
End If
PropertyChanged("Text")
End Set
End Property
Protected Sub PropertyChanged(ByVal propName As String)
Dim myHtmlControlDesignBehavior As IControlDesignerTag = Me.Tag
Dim myDataBindingCollection As DataBindingCollection
Dim myDataBinding1, myDataBinding2 As DataBinding
Dim myStringReplace1, myDataBindingExpression1, removedBinding, removedBindingAfterReplace, myDataBindingExpression2, myStringReplace2 As [String]
Dim removedBindings1(), removedBindings2() As String
Dim temp As Int32
If myHtmlControlDesignBehavior Is Nothing Then
Return
End If
myDataBindingCollection = DataBindings
' Use the DataBindingCollection constructor to
' create the myDataBindingCollection1 object.
' Then set this object equal to the
' DataBindings property of the control created
' by this custom designer.
Dim myDataBindingCollection1 As New DataBindingCollection()
myDataBindingCollection1 = DataBindings
myDataBindingCollection = DataBindings
If (myDataBindingCollection.Contains(propName)) Then
myDataBinding1 = myDataBindingCollection(propName)
myStringReplace1 = propName.Replace(".", "-")
If myDataBinding1 Is Nothing Then
myHtmlControlDesignBehavior.RemoveAttribute(myStringReplace1)
Return
End If
' DataBinding is not null.
myDataBindingExpression1 = [String].Concat("<%#", myDataBinding1.Expression, "%>")
myHtmlControlDesignBehavior.SetAttribute(myStringReplace1, myDataBindingExpression1)
Dim index As Integer = myStringReplace1.IndexOf("-")
Else
' Use the DataBindingCollection.RemovedBindings
' property to set the value of the removedBindings
' arrays.
removedBindings1 = DataBindings.RemovedBindings
removedBindings2 = DataBindings.RemovedBindings
temp = 0
While removedBindings2.Length > temp
removedBinding = removedBindings2(temp)
removedBindingAfterReplace = removedBinding.Replace("."c, "-"c)
myHtmlControlDesignBehavior.RemoveAttribute(removedBindingAfterReplace)
temp = temp & 1
End While
End If
' Use the DataBindingCollection.GetEnumerator method
' to iterate through the myDataBindingCollection object
' and write the PropertyName, PropertyType, and Expression
' properties to a file for each DataBinding object
' in the MyDataBindingCollection object.
myDataBindingCollection = DataBindings
Dim myEnumerator As IEnumerator = myDataBindingCollection.GetEnumerator()
While myEnumerator.MoveNext()
myDataBinding2 = CType(myEnumerator.Current, DataBinding)
Dim dataBindingOutput1, dataBindingOutput2, dataBindingOutput3 As [String]
dataBindingOutput1 = [String].Concat("The property name is ", myDataBinding2.PropertyName)
dataBindingOutput2 = [String].Concat("The property type is ", myDataBinding2.PropertyType.ToString(), "-", dataBindingOutput1)
dataBindingOutput3 = [String].Concat("The expression is ", myDataBinding2.Expression, "-", dataBindingOutput2)
WriteToFile(dataBindingOutput3)
myDataBindingExpression2 = [String].Concat("<%#", myDataBinding2.Expression, "%>")
myStringReplace2 = myDataBinding2.PropertyName.Replace(".", "-")
myHtmlControlDesignBehavior.SetAttribute(myStringReplace2, myDataBindingExpression2)
Dim index As Integer = myStringReplace2.IndexOf("-"c)
End While ' while loop ends
End Sub
Public Sub WriteToFile(ByVal input As String)
' The WriteToFile custom method writes
' the values of the DataBinding properties
' to a file on the C drive at design time.
Dim myFile As StreamWriter = File.AppendText("C:\DataBindingOutput.txt")
Dim encoder As New ASCIIEncoding()
Dim ByteArray As Byte() = encoder.GetBytes(input)
Dim CharArray As Char() = encoder.GetChars(ByteArray)
myFile.WriteLine(CharArray, 0, input.Length)
myFile.Close()
End Sub
End Class
Keterangan
Setiap ekspresi pengikatan data dalam kontrol server diwakili pada waktu desain oleh instans DataBinding kelas. Kontrol server apa pun yang berisi satu atau beberapa ekspresi pengikatan data memiliki DataBindingCollection objek yang berisi DataBinding objek. Koleksi ini dapat diakses melalui kelas yang Control mengimplementasikan IDataBindingsAccessor antarmuka. Saat Anda membuat desainer RAD kustom, gunakan implementasi tersebut untuk mengakses koleksi. Objek atau DataBindingCollection apa pun DataBinding yang terkait dengan kontrol server hanya ada pada waktu desain. Mereka tidak ada pada waktu proses dan, oleh karena itu, tidak dapat diakses selama run time.
Konstruktor
| Nama | Deskripsi |
|---|---|
| DataBinding(String, Type, String) |
Menginisialisasi instans baru dari kelas DataBinding. |
Properti
| Nama | Deskripsi |
|---|---|
| Expression |
Mendapatkan atau mengatur ekspresi pengikatan data yang akan dievaluasi. |
| PropertyName |
Mendapatkan nama properti kontrol server ASP.NET untuk mengikat data. |
| PropertyType |
Mendapatkan jenis .NET dari properti kontrol server ASP.NET terikat data. |
Metode
| Nama | Deskripsi |
|---|---|
| Equals(Object) |
Menentukan apakah objek yang ditentukan adalah instans DataBinding kelas yang sama dengan objek saat ini. |
| GetHashCode() |
Mengambil kode hash untuk instans DataBinding objek. |
| GetType() |
Mendapatkan Type instans saat ini. (Diperoleh dari Object) |
| MemberwiseClone() |
Membuat salinan dangkal dari Objectsaat ini. (Diperoleh dari Object) |
| ToString() |
Mengembalikan string yang mewakili objek saat ini. (Diperoleh dari Object) |
