Question

我知道它是否可能，但我需要的是通过它指针访问（使用和释放）TStream变量，将一个字符串参数传递给另一个函数。

这是＆＃34;不工作＆＃34;我想做的事情的例子：

public class DrawGraph
{
    public PlotModel MyModel { get; set; }

    public DrawGraph ()
    {

        var plotModel = new PlotModel {};

        plotModel.Title = "Test";

        var xaxis = new LinearAxis {
            Position = AxisPosition.Bottom
        };

        var yaxis = new LinearAxis {
            Position = AxisPosition.Left
        };

        yaxis.TickStyle = OxyPlot.Axes.TickStyle.Inside;
        xaxis.MinorTickSize = 20;
        yaxis.TicklineColor = OxyColors.Blue;

        plotModel.Axes.Add (xaxis);
        plotModel.Axes.Add (yaxis);

        var series1 = new LineSeries {
            StrokeThickness = 3,
            MarkerType = MarkerType.Circle,
            MarkerSize = 4,
            MarkerStroke = OxyColors.LimeGreen,
            MarkerStrokeThickness = 1
        };

        double[,] chartValues = new double[,] {{1437041279684.0156,1.0897299999999999},{1437041339421.4324,1.0896},{1437041397111.7322,1.0897100000000002},{1437041458595.2488,1.0898599999999998},{1437041519510.7329,1.08992},{1437041578914.1306,1.08983},{1437041639357.5877,1.0895100000000002},{1437041699721.0405,1.0895299999999999},{1437041758381.3958,1.0895000000000001},{1437041818605.84,1.08954},{1437041879932.3479,1.0894400000000002},{1437041939531.7568,1.08902}};

        for (int i = 0; i < chartValues.GetLength(0)/2; i++) {
            series1.Points.Add (new DataPoint (chartValues[i,0],chartValues[i,1]));
        }

        plotModel.Series.Add (series1);

        this.MyModel = plotModel;
    }
}

感谢您解决此问题的任何帮助！

Answer 1

TStream是一种引用类型。您的Stm变量包含指向流对象实例的指针。您希望传递此指针值，而不是本地变量的地址。这是固定代码：

procedure TForm1.Button1Click(Sender: TObject);
var
  Stm: TMemoryStream;
begin
  Stm := TMemoryStream.Create;
  try
    Memo.Lines.SaveToStream(Stm);
    Stm.Position := 0;
    Memo.Clear;
    Edit.Text := IntToStr(Integer(Stm));
  except
    Stm.Free;
    raise;
  end;
end;

procedure TForm1.Button2Click(Sender: TObject);
var
  Stm: TMemoryStream;
begin
  Stm := Pointer(StrToInt(Edit.Text));
  try
    Memo.Lines.LoadFromStream(Stm);
  finally
    Stm.Free;
  end;
end;

Delphi - 将变量指针作为字符串传递给另一个函数

1 个答案: