你可以复制下面文本框中的内容, 然后直接往窗体上贴, 以快速完成窗体设计: object DBGrid1: TDBGrid Left = 8 Top = 88 Width = 321 Height = 89 DataSource = DataSource1 TabOrder = 0 TitleFont.Charset = DEFAULT_CHARSET TitleFont.Color = clWindowText TitleFont.Height = -11 TitleFont.Name = 'Tahoma' TitleFont.Style = [] end object Button1: TButton Left = 382 Top = 88 Width = 75 Height = 25 Caption = 'Button1' TabOrder = 1 OnClick = Button1Click end object Button2: TButton Left = 382 Top = 129 Width = 75 Height = 25 Caption = 'Button2' TabOrder = 2 OnClick = Button2Click end object FDConnection1: TFDConnection Left = 34 Top = 24 end object FDPhysSQLiteDriverLink1: TFDPhysSQLiteDriverLink Left = 143 Top = 24 end object FDGUIxWaitCursor1: TFDGUIxWaitCursor Provider = 'Forms' Left = 260 Top = 24 end object FDQuery1: TFDQuery Connection = FDConnection1 Left = 344 Top = 24 end object DataSource1: TDataSource DataSet = FDQuery1 Left = 420 Top = 24 end object FDSQLiteFunction1: TFDSQLiteFunction DriverLink = FDPhysSQLiteDriverLink1 Active = True FunctionName = 'MyFun1' ArgumentsCount = 3 OnCalculate = FDSQLiteFunction1Calculate Left = 48 Top = 200 end object FDSQLiteFunction2: TFDSQLiteFunction DriverLink = FDPhysSQLiteDriverLink1 Active = True FunctionName = 'MyFun2' ArgumentsCount = 3 OnCalculate = FDSQLiteFunction2Calculate Left = 152 Top = 200 end
代码:
unit Unit1;interfaceuses Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics, Vcl.Controls, Vcl.Forms, Vcl.Dialogs, FireDAC.Stan.Intf, FireDAC.Stan.Option, FireDAC.Stan.Error, FireDAC.UI.Intf, FireDAC.Phys.Intf, FireDAC.Stan.Def, FireDAC.Stan.Pool, FireDAC.Stan.Async, FireDAC.Phys, FireDAC.Stan.ExprFuncs, FireDAC.VCLUI.Wait, FireDAC.Stan.Param, FireDAC.DatS, FireDAC.DApt.Intf, FireDAC.DApt, Vcl.Grids, Vcl.DBGrids, Data.DB, FireDAC.Comp.DataSet, FireDAC.Comp.Client, FireDAC.Comp.UI, FireDAC.Phys.SQLite, Vcl.StdCtrls, FireDAC.Phys.SQLiteWrapper;type TForm1 = class(TForm) FDConnection1: TFDConnection; FDPhysSQLiteDriverLink1: TFDPhysSQLiteDriverLink; FDGUIxWaitCursor1: TFDGUIxWaitCursor; FDQuery1: TFDQuery; DataSource1: TDataSource; DBGrid1: TDBGrid; Button1: TButton; Button2: TButton; FDSQLiteFunction1: TFDSQLiteFunction; FDSQLiteFunction2: TFDSQLiteFunction; procedure FormCreate(Sender: TObject); procedure Button1Click(Sender: TObject); procedure Button2Click(Sender: TObject); procedure FDSQLiteFunction1Calculate(AFunc: TSQLiteFunctionInstance; AInputs: TSQLiteInputs; AOutput: TSQLiteOutput; var AUserData: TObject); procedure FDSQLiteFunction2Calculate(AFunc: TSQLiteFunctionInstance; AInputs: TSQLiteInputs; AOutput: TSQLiteOutput; var AUserData: TObject); private { Private declarations } public { Public declarations } end;var Form1: TForm1;implementation{$R *.dfm}procedure TForm1.FormCreate(Sender: TObject);const strTable = 'CREATE TABLE MyTable(姓名 string(10), 语文 Integer, 数学 Integer, 英语 Integer)'; // 建一个学生成绩表begin { 建立一个成绩表, 并插入测试数据 } FDConnection1.Params.Add('DriverID=SQLite'); FDConnection1.ExecSQL(strTable); FDQuery1.ExecSQL('INSERT INTO MyTable(姓名, 语文, 数学, 英语) VALUES(:1, :2, :3, :4)', ['张三', 66, 77, 88]); FDQuery1.ExecSQL('INSERT INTO MyTable(姓名, 语文, 数学, 英语) VALUES(:1, :2, :3, :4)', ['李四', 77, 88, 99]); FDQuery1.Open('SELECT * FROM MyTable'); { 分别给两个 TFDSQLiteFunction 设定参数 } FDSQLiteFunction1.DriverLink := FDPhysSQLiteDriverLink1; FDSQLiteFunction1.FunctionName := 'MyFun1'; // 函数名 FDSQLiteFunction1.ArgumentsCount := 3; // 函数的参数个数 // FDSQLiteFunction1.OnCalculate := FDSQLiteFunction1Calculate; //在设计时建立 OnCalculate 事件更方便 FDSQLiteFunction1.Active := True; FDSQLiteFunction2.DriverLink := FDPhysSQLiteDriverLink1; FDSQLiteFunction2.FunctionName := 'MyFun2'; FDSQLiteFunction2.ArgumentsCount := 3; // FDSQLiteFunction2.OnCalculate := FDSQLiteFunction2Calculate; //在设计时建立 OnCalculate 事件更方便 FDSQLiteFunction2.Active := True;end;{ 调用 MyFun1 }procedure TForm1.Button1Click(Sender: TObject);begin FDQuery1.Open('SELECT 姓名, MyFun1(语文, 数学, 英语) AS 总分 FROM MyTable');end;{ 调用 MyFun2 }procedure TForm1.Button2Click(Sender: TObject);begin FDQuery1.Open('SELECT 姓名, MyFun2(语文, 数学, 英语) AS 平均分 FROM MyTable');end;{ 函数 MyFun1 的定义: 算总分 }procedure TForm1.FDSQLiteFunction1Calculate(AFunc: TSQLiteFunctionInstance; AInputs: TSQLiteInputs; AOutput: TSQLiteOutput; var AUserData: TObject);begin AOutput.AsInteger := AInputs[0].AsInteger + AInputs[1].AsInteger + AInputs[2].AsInteger;end;{ 函数 MyFun2 的定义: 算平均分 }procedure TForm1.FDSQLiteFunction2Calculate(AFunc: TSQLiteFunctionInstance; AInputs: TSQLiteInputs; AOutput: TSQLiteOutput; var AUserData: TObject);begin AOutput.AsFloat := (AInputs[0].AsInteger + AInputs[1].AsInteger + AInputs[2].AsInteger) / 3;end;end. 效果图:
