Creating variables using the New keyword

Summary

This topic shows how to declare and instantiate new variables by utilizing documents in the help system.

In this topic

About creating variables using the New keyword
Class documents
Interface documents

About creating variables using the New keyword

To instantiate a new object based on an ArcObjects class, use the "New" keyword in the .NET syntax. The class and interface documents are the types of help documents in the ArcObjects namespace reference that provide the necessary information to accomplish this task.

Class documents

In the ArcObjects namespace reference, each class has a help document. These documents detail the name of the class, library to which the class belongs (for example, ArcMapUI, Carto, Server, and so on), platforms on which the class is supported, and all interfaces used.

In the class document, note specifically the name of the class in the title and any interfaces used. The name of the class is the variable instantiation and the interface is the variable declaration.

For example, to create an AddDataDialog object, navigate to the AddDataDialogClass help document and use the title and interfaces to generate the code. See the following screen shot and code example that shows the New keyword:

Screen shot showing AddDataDialog and the New keyword in the code example.

[VB.NET]


        Public Class Class2
    
    Public Sub Test()
        
        Dim addDataDialog As IAddDataDialog = New AddDataDialogClass
        
    End Sub
    
End Class

[C#]


        public class Class2
{
    public void test()
    {
        IAddDataDialog addDataDialog = new AddDataDialogClass();
    }
}

If multiple interfaces are available in the class help document, choose the one that best suits your programming needs. Click an interface's link to view its properties, methods, and events.

Interface documents

Interface documents contain the following information that complements the class help documents:

Interface name in the title
Classes that implement the interface

The name of the interface is the variable declaration and the class is the variable instantiation.

For example, to create an AddDataDialog object with the IAddDataDialog interface displayed in the reading pane, translates into the .NET code. See the following screen shot and code example that shows the New keyword:

Screen shot showing IAddDataDialog and the New keyword in the code example.