Question

I’m writing an application to log microscope usage but the following piece of code generates an error E2010 incompatible types “WideString’ and “TDataFile” at the line that reads: SetLength(Items, FileSize(F)); I have narrowed down the problem to FileSize(F), just a number instead gives no error and trying to assign i := fileSize(F); where i is an integer gives the same error.

type
  TData = record
    Status : integer; // 0=operational 1=maintenance 2=fault
    OperatorName : string[255];
    Client : string[255];
    Specimen : string[255];
    Memo : string[255];
    TEM : TTEM;
    SEM : TSEM;
    FIB : TFIB;
    StartTime : string[22]; // YYYY/MM/DD HH:MM:SS AM
    FinishTime : string[22];
    DataFileName : string[255];
  end;

  TDataFile = File of TData;

  TDataArray = array of TData

function LoadAllData(FileName: string; var Items: TDataArray):boolean;
// Loads contents of Datafile into Items and returns true if successful else false
var
  F : TDataFile;
  i : integer;
begin
  AssignFile(F, FileName);
  try
    try
      Reset(F);
      SetLength(Items, FileSize(F)); // This is the problem line
      for i := 0 to High(Items) do
        Read(F, Items[i]);
      LoadAllData := true;
    except
      LoadAllData := false;
    end;
  finally
    CloseFile(F);
  end;
end;

I’m using delphi 2010 on Win7 64bit. Does anyone know why this is happening? Writing a small console app just to test i := FileSize(F); works without a problem….

Answer 1

It seems that you have a function called FileSize declared in another unit or part of your code, something like

function FileSize(const f : WideString):integer;
begin

//

end;

to resolve the issue, add the unit name of the function (in this case System) before the function name to explicitly call the FileSize function.

SetLength(Items, System.FileSize(F));