DataBinding Class
Contains information about a single data-binding expression in an ASP.NET server control, which allows rapid-application development (RAD) designers, such as Microsoft Visual Studio, to create data-binding expressions at design time. This class cannot be inherited.
Assembly: System.Web (in System.Web.dll)
| Name | Description | |
|---|---|---|
![]() | DataBinding(String, Type, String) | Initializes a new instance of the DataBinding class. |
| Name | Description | |
|---|---|---|
![]() | Expression | Gets or sets the data-binding expression to be evaluated. |
![]() | PropertyName | Gets the name of the ASP.NET server control property to bind data to. |
![]() | PropertyType | Gets the .NET Framework type of the data-bound ASP.NET server control property. |
| Name | Description | |
|---|---|---|
![]() | Equals(Object) | Determines whether the specified object is the same instance of the DataBinding class as the current object.(Overrides Object.Equals(Object).) |
![]() | GetHashCode() | Retrieves the hash code for an instance of the DataBinding object.(Overrides Object.GetHashCode().) |
![]() | GetType() | |
![]() | ToString() | Returns a string that represents the current object.(Inherited from Object.) |
Each data-binding expression in a server control is represented at design time by an instance of the DataBinding class. Any server control that contains one or more data-binding expressions has a DataBindingCollection object that contains the DataBinding objects. This collection is accessible through the Control class implementing the IDataBindingsAccessor interface. When you create a custom RAD designer, use that implementation to access the collection. Any DataBinding or DataBindingCollection objects associated with a server control exist only at design time. They do not exist at run time and, therefore, are not accessible during run time.
The following code example creates a DataBinding object and sets it equal to an existing object in the control's DataBindingCollection collection that has a propertyName parameter with a value of Text. If the collection contains a DataBinding object with a propertyName value of Text, this code returns the value of the object's Expression property. If there is no such object, it returns an empty string ("").
// 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(); } }
Available since 1.1
Any public static ( Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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