如何使用 DBLookupComboBox 在 Delphi 中的表单页面之间移动

Question

我对 Delphi 中的 DBLookupComboBox 组件有疑问。我想使用 DBLookupComboBox 组件在 Delphi 程序中的表单页面之间移动。

例如，当我从 DBLookupComboBox 列表中选择名称“ahmed”时，它将移动到表格 4，而当我从 DBLookupComboBox 列表中选择名称“fatima”时，它将移动到表格 5，如图所示下面。

Delphi中此操作的适当代码是什么？

Answer 1

这是一个简单的代码来完成您的要求。在此代码中，我使用 TClientDataset 来存储数据以填充 TComboBox。当然你可以使用你喜欢的数据集。请注意，我使用的是 TCombobox 而不是 DBLookupCombobox。我觉得更好。

我使用 TDictionary link 名称和表格。必须将表单添加到项目和 auto-created。我在两个单位中创建了两种形式：UnitAhmed 和 UnitMohamed。这些只是重命名并保存在其单元中的空表格。

unit Unit6;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Classes,
  Vcl.Graphics, Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls,
  Data.DB, Datasnap.DBClient, Vcl.DBCtrls,
  System.Generics.Collections,
  UnitAhmedForm,
  UnitMohamedForm;

type
  TMainForm = class(TForm)
    ComboBox1: TComboBox;
    procedure FormCreate(Sender: TObject);
    procedure ComboBox1Click(Sender: TObject);
    procedure FormShow(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    ClientDataSet1 : TClientDataset;
    FDictionary : TDictionary<String, TForm>;
    procedure SelectedFormClose(Sender: TObject; var Action: TCloseAction);
  end;

var
  MainForm: TMainForm;

implementation

{$R *.dfm}

procedure TMainForm.ComboBox1Click(Sender: TObject);
var
    SelectedForm : TForm;
begin
    // Try to find the name selected in the combobox and the associated form
    if not FDictionary.TryGetValue(ComboBox1.Text, SelectedForm) then begin
        ShowMessage('Not found');
        Exit;
    end;
    // The name and form are found, make it visible
    SelectedForm.Visible := TRUE;
    // Assign an OnClose event to make mainform visible when the selected
    // form is closed
    SelectedForm.OnClose := SelectedFormClose;
    // Hide the main form
    Visible              := FALSE;
end;

procedure TMainForm.SelectedFormClose(Sender: TObject; var Action: TCloseAction);
begin
    // Make the main form visible
    Visible := TRUE;
end;


procedure TMainForm.FormCreate(Sender: TObject);
begin
    // Create an in-memory dataset with one single field
    ClientDataSet1 := TClientDataset.Create(Self);
    ClientDataSet1.FieldDefs.Add('Name', ftString, 32);
    ClientDataSet1.IndexFieldNames := 'Name';
    ClientDataSet1.CreateDataSet;

    // Populate the dataset with two records
    ClientDataSet1.Open;
    ClientDataSet1.Append;
    ClientDataSet1.FieldByName('Name').AsString := 'ahmed';
    ClientDataSet1.Post;
    ClientDataSet1.Append;
    ClientDataSet1.FieldByName('Name').AsString := 'mohamed';
    ClientDataSet1.Post;

    // Fill the combobox with the just created dataset content
    ClientDataSet1.First;
    while not ClientDataSet1.Eof do begin
        ComboBox1.Items.Add(ClientDataSet1.FieldByName('Name').AsString);
        ClientDataSet1.Next;
    end;
end;

procedure TMainForm.FormDestroy(Sender: TObject);
begin
    FreeandNil(FDictionary);
end;

procedure TMainForm.FormShow(Sender: TObject);
begin
    // Create the dictionary which associate a name and a form.
    // We cannot do that in the FormCreate because at that time the other
    // forms are not created yet (By auto-create mechanism)
    // Here in the OnShow event handler, all forms are already created
    FDictionary := TDictionary<String, TForm>.Create;
    FDictionary.Add('ahmed',   AhmedForm);
    FDictionary.Add('mohamed', MohamedForm);
end;

end.

如何使用 DBLookupComboBox 在 Delphi 中的表单页面之间移动

How can move between the forms pages in Delphi using DBLookupComboBox

delphi

pascal