TClientDataSet错误:“缺少数据提供者或数据包" [英] TClientDataSet error: "Missing data provider or data packet"

问题描述

我正在用Delphi中的代码创建一个TClientDataSet和TDataSetProvider，并从TUniQuery(Devart UniDAC)加载数据.设置数据集提供程序和clientdataset的属性后，我尝试打开clientdataset并获取运行时异常:缺少数据提供程序或数据包".

I'm creating a TClientDataSet and TDataSetProvider in code in Delp and loading the data from a TUniQuery (Devart UniDAC). After setting the properties for the dataset provider and the clientdataset, I try to open the clientdataset and get the runtime exception: "Missing data provider or data packet".

我不确定为什么会这样，如果有人能指出到底是什么错误，我会很高兴.

I'm not sure why its happening and would be glad if anyone could point out what exactly is wrong.

这是我的代码:

//uq is a TUniQuery correctly set to an active TUniConnection

cdsFirstNames := TClientDataSet.Create(nil);
dspFirstNames := TDataSetProvider.Create(nil);
try
  uq.SQL.Text := 'SELECT * FROM firstnames;';
  uq.Prepared := True;
  // uq.Open;
  dspFirstNames.Name := 'dspFirstNames';
  dspFirstNames.DataSet := uq;
  cdsFirstNames.ProviderName := 'dspFirstNames';
  cdsFirstNames.Open;  // <--- Exception occurs here!
  uq.Close;
  showmessage(IntToStr(cdsFirstNames.RecordCount));

推荐答案

如果DatasetProvider没有所有者，则ClientDataSet无法获取对该提供程序的引用.

If DatasetProvider has no owner, ClientDataSet can not obtain a reference to the provider.

所以使用

...Create(Self); 

代替

...Create(nil);

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