Parameters to variant array

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Convert data of the ADO control to a variant array

 

Use the clientdataset datarequest method to upload the variant array

 

Trigger the ondatarequest event of datasetprovider on the server, and parse the uploaded variant array in ondatarequest.

 

Number of operations performed on the Root Node of the ADO control on the server

 

Returns the result of the operation to the variant array and returns the client.

 

The client parses the variant array and displays the data.

 

// Convert parameters to a variant array

Function parameterstovariant (PAR: tparameters; procedurename: variant): olevariant;

VaR

Tmpv: variant;

N, I: integer;

Begin

Tmpv: = vararraycreate ([0, par. Count * 5 + 1], varvariant );

Tmpv [0]: = procedurename;

Tmpv [par. Count * 5 + 1]: = 'this is fro 93 ';

N: = 0;

I: = 0;

While par. Count> I do begin

Tmpv [n + 1]: = par. items [I]. Name;

Tmpv [n + 2]: = par. items [I]. datatype;

Tmpv [N + 3]: = par. items [I]. direction;

Tmpv [n + 4]: = par. items [I]. size;

Tmpv [n + 5]: = par. items [I]. value;

I: = I + 1;

N: = N + 5;

End;

Result: = tmpv;

End;

 

//// Convert the variant array to parameters

Function varianttoparameters (input: variant; par: tparameters): variant;

VaR

N, I: integer;

Begin

N: = 0;

I: = 0;

While vararrayhighbound (input, 1)> (n + 5) Do begin

Par. createparameter (input [n + 1], input [n + 2], input [N + 3], input [n + 4], input [n + 5]);

N: = N + 5;

End;

Result: = true;

End;

 

// The general purpose of Proc is called by.Program

Procedure midasadoproc (myproc: tadostoredproc; myclientdataset: tclientdataset );

VaR

INS, outs: variant;

Begin

INS: = parameterstovariant (myproc. parameters, myproc. procedurename );

Outs: = myclientdataset. datarequest (INS );

Myproc. procedurename: = outs [0];

Myproc. Parameters. Clear;

Varianttoparameters (outs, myproc. Parameters );

End;

End.

 

Function tmidasadoproc. datasetprovider1datarequest (Sender: tobject;

Input: olevariant): olevariant;

Begin

If varisarray (input) then

Begin

If input [vararrayhighbound (input, 1)] = 'this is fro 93' then

Begin // call the Stored Procedure

Form1.caption: = 'proc = '+ input [0];

Self. adostoredproc1.procedurename: = input [0];

Self. adostoredproc1.parameters. Clear;

Varianttoparameters (input, self. adostoredproc1.parameters );

Self. adostoredproc1.execproc; Result: = parameterstovariant (self. adostoredproc1.parameters, self. adostoredproc1.procedurename );

End else

Form1.caption: = 'source information is not unknown in Stored Procedure information ';

End else

Form1.caption: = 'unknown source information ';

End;

 

Procedure tform1.button1click (Sender: tobject );

Begin

If self. socketconnection1.connected = false then self. socketconnection1.open;

Self. adostoredproc1.parameters. Clear;

Self. adostoredproc1.procedurename: = 'testdelphi '; // modify the name of the stored procedure in the local directory by dynamically calling

Self. adostoredproc1.parameters. createparameter ('ins', ftstring, pdinput, 2000, self. edit1.text );

Self. adostoredproc1.parameters. createparameter ('outs', ftstring, pdoutput, 2000, 'null ');

// The original self. adostoredproc1.execproc; is changed to the following

Midasadoproc (self. adostoredproc1, self. clientdataset1 );

Showmessage ('stored procedure returned '+ self. adostoredproc1.parameters. paramvalues ['outs']);

End;