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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