CallByName Method

Interaction.CallByName Method (Object, String, CallType, Object[])


Executes a method on an object, or sets or returns a property on an object.

Namespace:   Microsoft.VisualBasic
Assembly:  Microsoft.VisualBasic (in Microsoft.VisualBasic.dll)

public static object CallByName(
	object ObjectRef,
	string ProcName,
	CallType UseCallType,
	params object[] Args


Type: System.Object

Required. Object. A pointer to the object exposing the property or method.

Type: System.String

Required. String. A string expression containing the name of the property or method on the object.

Type: Microsoft.VisualBasic.CallType

Required. An enumeration member of type CallType representing the type of procedure being called. The value of CallType can be Method, Get, or Set.

Type: System.Object[]

Optional. ParamArray. A parameter array containing the arguments to be passed to the property or method being called.

Return Value

Type: System.Object

Executes a method on an object, or sets or returns a property on an object.

Exception Condition

Invalid UseCallType value; must be Method, Get, or Set.

The CallByName function is used at runtime to get a property, set a property, or invoke a method.

In the following example, the first line uses CallByName to set the Text property of a text box, the second line retrieves the value of the Text property, and the third line invokes the Move method to move the text box.

' Imports statements must be at the top of a module.
Imports Microsoft.VisualBasic.CallType
Sub TestCallByName1()
    'Set a property.
    CallByName(TextBox1, "Text", CallType.Set, "New Text")

    'Retrieve the value of a property.
    MsgBox(CallByName(TextBox1, "Text", CallType.Get))

    'Call a method.
    CallByName(TextBox1, "Hide", CallType.Method)
End Sub

The next example uses the CallByName function to invoke the Add and Item methods of a collection object.

Public Sub TestCallByName2()
    Dim col As New Collection()

    'Store the string "Item One" in a collection by 
    'calling the Add method.
    CallByName(col, "Add", CallType.Method, "Item One")

    'Retrieve the first entry from the collection using the 
    'Item property and display it using MsgBox().
    MsgBox(CallByName(col, "Item", CallType.Get, 1))
End Sub

.NET Framework
Available since 1.1
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