Parameters转换为Variant数组
http://www.ccw.com.cn/applic/prog/htm2003/20030423_096DZ.htm
ado控件的參數轉化為Variant数组
使用ClientDataSet的DataRequest方法把Variant数组上传
触发服务器DataSetProvider的OnDataRequest事件，在OnDataRequest对上传的Variant数组进行解析
服務器上的ADO控件根據上傳的參數操作數據庫
把操作的結果轉換為Variant数组，下發客戶端
客戶端解析Variant数组，顯示數據
//Parameters转换为Variant数组
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 Midas';
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;
////Variant数组转换到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;
//MIDAS调用PROC的通用程序
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 Midas' then
begin //调存储过程
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:='来源信息非存储过程信息不明';
end else
Form1.Caption:='来源信息不明';
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
if self.SocketConnection1.Connected=false then self.SocketConnection1.Open;
self.ADOStoredProc1.Parameters.Clear;
self.ADOStoredProc1.ProcedureName:='TESTDELPHI'; //动态调用在本处改存储过程名
self.ADOStoredProc1.Parameters.CreateParameter('INS',ftString,pdInput,2000, self.Edit1.Text);
self.ADOStoredProc1.Parameters.CreateParameter('OUTS',ftString,pdOutput,2000,'NUll');
//原来的self.ADOStoredProc1.ExecProc; 改为下面的
MidasAdoProc(self.ADOStoredProc1,self.ClientDataSet1);
ShowMessage('存储过程返回'+self.ADOStoredProc1.Parameters.ParamValues['OUTS']);
end;