Use DLL compiled in Delphi 7 in C#

Question

I need to use a DLL (Hardware ID Extractor) made in Delphi 7 in my C# application.

The functions exported by this DLL are:

Exported functions (all using short strings)

// CPU
function GetCPUSpeed: Double;
function CPUFamily: ShortString; { Get cpu identifier from the windows registry }
function GetCpuTheoreticSpeed: Integer; { Get cpu speed (in MHz) }
function IsCPUIDAvailable: Boolean; Register;
function GetCPUID (CpuCore: byte): ShortString;
Function GetCPUVendor: ShortString;

// RAM
function MemoryStatus (MemType: Integer): cardinal; { in Bytes }
function MemoryStatus_MB (MemType: Integer): ShortString; { in MB }

// HDD
function GetPartitionID (Partition : PChar): ShortString; { Get the ID of the specified patition. Example of parameter: 'C:' }
function GetIDESerialNumber(DriveNumber: Byte ): PChar; { DriveNr is from 0 to 4 }

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How to map Delphi string to C#?

Answer 1

Here's an example of how you could declare the GetCPUSpeed function in C#:

class Program
{
    [DllImport("the_name_of_the_delphi_library.dll")]
    public static extern double GetCPUSpeed();

    static void Main(string[] args)
    {
        double cpuSpeed = GetCPUSpeed();
        Console.WriteLine("CPU speed: {0}", cpuSpeed);
    }
}

And there are the other declarations you could try:

[DllImport("the_name_of_the_delphi_library.dll")]
public static extern string CPUFamily();

[DllImport("the_name_of_the_delphi_library.dll")]
public static extern int GetCpuTheoreticSpeed();

[DllImport("the_name_of_the_delphi_library.dll")]
public static extern bool IsCPUIDAvailable();

[DllImport("the_name_of_the_delphi_library.dll")]
public static extern string GetCPUID(byte cpuCore);

[DllImport("the_name_of_the_delphi_library.dll")]
public static extern string GetCPUVendor();

[DllImport("the_name_of_the_delphi_library.dll")]
public static extern uint MemoryStatus(int memType);

[DllImport("the_name_of_the_delphi_library.dll")]
public static extern string MemoryStatus_MB(int memType);

[DllImport("the_name_of_the_delphi_library.dll")]
public static extern string GetPartitionID(char partition);

[DllImport("the_name_of_the_delphi_library.dll")]
public static extern string GetIDESerialNumber(byte driveNumber);