Changes have been made to support 64-bit .NET 2.0. These changes might require minor code changes so that existing applications work correctly. This document describes these changes in detail. There are two general areas:

1. Changed code patterns
2. Windows API declarations for some callbacks and records

1. Case statements Using a handle in a case statement no longer compiles. Replace statements like this:

case Msg.WParam of

with one of the following:

case Msg.WParam.ToInt64 of  // VCL.NET specific
case Int64(Msg.WParam) of   // Compatibile with VCL/Win32

2. Casting enumerations A handle can no longer be directly type cast to an enumerated type. Replace code like this:

LEnum := TEnum(GetWindowLong(...));

with this:

LEnum := TEnum(GetWindowLong(...).ToInt64);

3. Using handles with sets Overloading set operators isn’t supported, so code such as:

if Msg.WParam in [1..5] then

must be replaced with one of the following:

if Msg.WParam.ToInt64 in [1..5] then    // VCL.NET specific
if Int64(Msg.WParam) in [1..5] then     // Compatibile with VCL/Win32

4. Indexing into arrays Using a handle to index into an array no longer compiles. Code such as this:

S := StrArray[Msg.WParam];

must be changed to one of the following:

S := StrArray[Msg.WParam.ToInt64];  // VCL.NET specific
S := StrArray[Int64(Msg.WParam)];   // Compatibile with VCL/Win32

5. Assuming a specific handle size Code that is expected to run on 64-bit platforms should not assume the value of a handle or an IntPtr is in the Int32 range. In the case of an IntPtr, the ToInt32 method throws an overflow exception if it doesn't. Code such as this:

LIntPtr := IntPtr.Create(Buffer.ToInt32 + 10);

needs to be changed to this form:

LIntPtr := IntPtr.Create(Buffer.ToInt64 + 10);

Similarly, the following code:

var
   DC: HDC;
begin
   ...
   SendMessage(Window, Message, Integer(DC), 0);
end;

must be replaced by:

var
   DC: HDC;
begin
   ...
   SendMessage(Window, Message, WPARAM(DC), 0);
end;

1. Examine the first column of the table below to determine if you have used any of these units.
2. If you have used any unit, determine if you have used any of the callbacks for that unit listed in the second column of the table.
3. For each occurrence of such an callback, change the parameters noted in column 3 appropriately.

1. Examine the first column of the table below to determine if you have used any of these units.
2. If you have used any unit, determine if you have used any of the records for that unit listed in the second column of the table.
3. For each such record, find all places where a field was passed as a var parameter that has been changed to a property and modify the code appropriately. The compiler warns you whether you need to update or not.