The release number of this article has been CHS312390
For Microsoft Visual Basic .NET versions of this article, see
312389.
This task content
summary
Step-by-step example
Summary This article describes how to use Visual C # .NET
TOARRAY (TYPE) method Returns a strong type of array.
ArrayList
TOARRAY method returns
An array of Object types. can not be used
TOARRAY is not parametric implementation
The Object array is converted to the array type you want. For example, if you add some Customer objects to
In ArrayList, the base list cannot be changed to the Customer array. This will result in failure of the following statements and happen to occur:
Customer [] Customer = (Customer []) MyArrayList.toArray (); To return to the strong type array, use the object type as a parameter to accept
TOARRAY overload method. For example, the following statement can be successfully performed:
Customer [] Customer = (Customer []) MyArrayList.toArray (TypeOf (Customer);
Remarks: C # does not allow implicit conversion, so you must explicitly convert
The result of the ToArray method.
important:
All elements of ArrayList must be the same object type. If you will contain a heterogeneous object
ArrayList is converted to a specific type, then
The ToArray method will fail.
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Step-by-step example
Start a new console application project in Visual C # .NET. Replace the code in class1.cs to the following code: USING SYSTEM;
Using system.collections;
Class class1
{
[Stathread]
Static void main (string [] args)
{
Customer C = New Customer ();
c.cname = "anonymous";
ArrayList Al = New ArrayList ();
Al.Add (c);
Object [] carray = al.toArray ();
// Display the Type of the arraylist.
CONSOLE.WRITELINE (Carray.gettype ());
// UNComment the next line to reproduce the invalidcastexception.
// Customer [] CustArray = (Customer []) (al.toArray ());
// Comment the next line to reproduce the invalidcastexception.
Customer [] CustArray = (Customer []) Al.toArray (TypeOf (Customer));
Console.writeLine (Custarray.gettype ());
}
}
Class Customer
{
Public String CName;
}
Press CTRL F5 combination to generate and run the project. (Ctrl F5 Combined Key Allows the console window to keep open state.) To recover INVALIDCASTEXCEPTION, follow the two annotations in the sample code. Back to top
The information in this article applies to:
Microsoft Visual C # .NET (2002)
Recent Updated: 2002-2-24 (1.0) Keyword Kbhowto KbhowTomaster KB312390
