如何解决如何使用DBLookupComboBox在Delphi中的表单页面之间移动
我对Delphi中的DBLookupComboBox组件有疑问。我想使用DBLookupComboBox组件在Delphi程序的表单页面之间移动。
例如,当我从DBLookupComboBox列表中选择名称“ ahmed”时,它将移至表格4;当我从DBLookupComboBox列表中选择名称“ fatima”时,它将移至表格5,如下图所示。
在Delphi中进行此操作的合适代码是什么?
解决方法
这是执行您要求的简单代码。在此代码中,我使用TClientDataset存储数据以填充TComboBox。当然,您可以使用自己喜欢的数据集。请注意,我使用的是TCombobox,而不是DBLookupCombobox。我认为这更好。
我使用TDictionary链接名称和表格。表单必须添加到项目中并自动创建。我在两个单元中创建了两种形式:UnitAhmed和UnitMohamed。这些只是重命名并保存在其单元中的空表单。
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.
版权声明:本文内容由互联网用户自发贡献,该文观点与技术仅代表作者本人。本站仅提供信息存储空间服务,不拥有所有权,不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容, 请发送邮件至 dio@foxmail.com 举报,一经查实,本站将立刻删除。