featureinfo.pas

GIS地理信息系统开发。 大名鼎鼎的MAPX＋DELPHI7.0软件开发

unit featureInfo;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, ComObj;

type
  TfeatureInfoForm = class(TForm)
    CloseButton: TButton;
    updateButton: TButton;
    columnNameLabel: TLabel;
    columnNameCombo: TComboBox;
    valueLabel: TLabel;
    valueEditBox: TEdit;
    procedure CloseButtonClick(Sender: TObject);
    procedure FormActivate(Sender: TObject);
    procedure columnNameComboChange(Sender: TObject);
    procedure updateButtonClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  featureInfoForm: TfeatureInfoForm;
  f : Variant;     // Used for storing feature chosen
  lyr : Variant;   // layer that features comes from

implementation

uses MainMapForm, MapXLib_TLB;

{$R *.DFM}

procedure TfeatureInfoForm.CloseButtonClick(Sender: TObject);
begin
     VarClear(f);
     VarClear(lyr);
     Close;
end;

procedure TfeatureInfoForm.FormActivate(Sender: TObject);
var
   i : Integer;
   flds : Variant;
   ds : Variant;
   unusedParam : OleVariant;
begin
     TVarData(unusedParam).vType := varError;
     TVarData(unusedParam).vError := 2147614724; // DISP_E_PARAMNOTFOUND;
     lyr := MainMapForm.EditLayer;
     f := MainMapForm.infoFeature;
  // Add Dataset using layer that feature resides in.  This done to get the
  // list of fields that are in the table
     ds := MainMap.Map1.Datasets.Add(miDatasetLayer, lyr,unusedParam, unusedParam, unusedParam, unusedParam, unusedParam, unusedParam);
     flds := ds.fields;
  // Add all the fields of the table to a comboBox
     columnNameCombo.Clear;
     for i := 1 to flds.count do
         columnNameCombo.Items.Add(flds.Item[i].name);
     columnNameCombo.ItemIndex := 0;
  // Set the layers KeyField to be the first field in the table
     lyr.KeyField := columnNameCombo.Text;
  // fill text box with value for first keyField for selected feature
     valueEditBox.Text := f.KeyValue;

     VarClear(flds);
     VarClear(ds);
end;

procedure TfeatureInfoForm.columnNameComboChange(Sender: TObject);
begin
     // Reset the keyField for the layer & Assign new key value to
     // the text box
     lyr.KeyField := columnNameCombo.Text;
     valueEditBox.Text := f.KeyValue;
end;

procedure TfeatureInfoForm.updateButtonClick(Sender: TObject);
begin
     // update the features keyValue with data in text box
     f.KeyValue := valueEditBox.Text;
     f.upDate;
end;

end.