TFloatField Class

TFloatField represents a field that contains floating-point values in a dataset.

Pascal

TFloatField = class(TNumericField);

C++

class TFloatField : public TNumericField;

File

Description

TFloatField encapsulates the fundamental behavior common to numeric data. Floating-point fields can hold values in the range from (positive or negative) 5.0 * 10^-324 to 1.7 * 10^308 with an accuracy of 15 digits. TFloatField introduces new properties to convert between integer values and other data types, to control the precision of numbers that the field will permit, and to format the value for display purposes.

If you use the Fields editor at design time to create a persistent field component for the float field, you can access it by name at runtime. When using dynamic field components, you can access the TFloatField instance using the dataset's Fields property or FieldByName method.

Delphi Examples:

Copy Code

{
This example requires a button, a test edit, and a populated
ClientDataSet.  Pipe the ClientDataSet through a DataSource
to a DGGrid or DBNavigator to control the current field.
Cast the data correctly according to the field type when
assigning to the test edit.
}

{$IFNDEF UNICODE}
uses SwSystem;
{$ENDIF}

procedure TForm1.Button1Click(Sender: TObject);
var MyBuffer: Pointer;
begin
{ Retrieve the "raw" data from Field1 }
with CDS.Fields[0] do
  begin
    if not IsBlob then { this does not work for BLOB fields }
    begin
      { Allocate space }
      MyBuffer:= GetMemory(DataSize);
      try
        if not GetData(MyBuffer) then
          MessageDlg(DisplayName + ' is NULL', mtInformation, [mbOK], 0)
        else
          { Do something with the data };
          Edit1.Text:= string(PAnsiChar(MyBuffer)); // for a stringfield
      finally
        { Free the space }
        FreeMem(MyBuffer, DataSize);
      end;
    end;
  end;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
{$IFDEF UNICODE}
  CDS.LoadFromFile(GetCurrentDir + '\CDS.XML');
{$ELSE}
  CDS.LoadFromFile(gsAppPath + 'CDS.XML');
{$ENDIF}
end;