Delphi combination of TDataSetProvider, TDataSet, TAdoQuery, TDataSource, TDataModule control use

Original link: http://www.cnblogs.com/OSKnown/p/8624761.html

Delphi combination of TDataSetProvider, TDataSet, TAdoQuery, TDataSource control use

As usual on the first control layout diagram:

1, File-New-VCL ​​Forms Application, fill in one by one to find the controls

Use controls: Button, TDataSetProvider, TDataSet, TAdoQuery, TDataSource, DbgridEh

 

Set point to the relationship between the controls:

  1> ds1 ds2 point of DataSet

  2> dtsprvdr1 DataSet point of qry1

  3> ds2 of ProviderName point dtsprvdr1

  4> DbGrideh the DataSource point ds1

2、File-New-Other-DataModule，确定

Add a Adoconnection control for even connect to the database

For convenience, simply double-click the control, configure the connection string

save document

3, this time back to the main form pas file, the new reference DataModual upper unit,

      Qry1 found in the main window, set his DataSource, pointing DataModule5.ADOConnection1

4, to increase the SQL property qry1 statement to query, for example: select * from testTable

5, the main form pas file increasing function:

 1 procedure GetConnected(Conn: TADOConnection);
 2 begin
 3   if Conn.Connected = False then
 4   begin
 5     Conn.Connected := True;
 6   end;
 7 end;
 8 
 9 function QuerySql(Sql: string; Conn: TADOConnection): boolean;
10 var
11   AdoQuery:TADOQuery;
12 begin
13   Result := False;
14   try
15     try
16       GetConnected(Conn);
17       An AdoQuery:. = TADOQuery the Create ( nil );     // must create an instance of the class 
18 is        AdoQuery.Close;
 . 19        AdoQuery.Connection: = Conn;
 20 is        AdoQuery.SQL.Clear;
 21 is        AdoQuery.SQL.Add (the Sql);
 22 is        an AdoQuery .Open;
 23 is        the Result: = AdoQuery.RecordCount> 0 ;
 24      the except 
25        ON E: Exception do 
26 is        the begin 
27          the ShowMessage ( ' statement: ' + the Sql + # 13 is # 10 + 'Exception class name: ' + E.ClassName + # 13 # 10 + ' exception message: ' + e.Message);
 28  
29          Application.MessageBox ( ' ! Querying the database fails, please refer to ' , ' tips ' , MB_OK + MB_ICONINFORMATION );
 30          the Result: = False;
 31 is        End ;
 32      End ;
 33 is    the finally 
34 is    End ;
 35  End ;

6, double-click the Button button:

1   QuerySql('select * from testTable',DataModule5.ADOConnection1);
2   ds2.Active := False;
3   ds2.Active := True;

7, ok, save, compile and run

 

Reproduced in: https: //www.cnblogs.com/OSKnown/p/8624761.html