Delphi:Clientdataset:.Open 上的 EDatabaseError; 设置了 ProviderName
所以我有这段代码来处理客户端按模式发送的内容。 如果他发送“getBENUds”,服务器将使用 SaveToString 方法发回该表的数据集。
然后,将其发送给客户端。 (我正在使用 Synapse)。
procedure TTCPSocketThrd.Execute;
var s: String;
strm: TMemoryStream;
ADO_CON: TADOConnection;
ADO_QUERY: TADOQuery;
DS_PROV: TDataSetProvider;
DS_CLIENT: TClientDataSet;
begin
CoInitialize(nil);
Sock := TTCPBlockSocket.Create;
try
Sock.Socket := CSock;
Sock.GetSins;
with Sock do
begin
repeat
if terminated then break;
s := RecvTerminated(60000,'|');
if s = 'getBENUds' then
begin
//ini ADO_CON
ADO_CON := TADOConnection.Create(Form1);
ADO_CON.ConnectionString := 'not for public';
ADO_CON.LoginPrompt := false;
ADO_CON.Provider := 'SQLOLEDB.1';
ADO_CON.Open;
//ini ADO_QUERY
ADO_QUERY := TADOQuery.Create(ADO_CON);
ADO_QUERY.Connection := ADO_CON;
//ini DS_PROV
DS_PROV := TDataSetProvider.Create(ADO_CON);
DS_PROV.DataSet := ADO_QUERY;
//ini DS_CLIENT
DS_CLIENT := TClientDataSet.Create(ADO_CON);
DS_CLIENT.ProviderName := 'DS_PROV';
//SQLQUERY Abfrage
ADO_QUERY.SQL.Clear;
ADO_QUERY.SQL.Add('SELECT * FROM BENU');
ADO_QUERY.Open;
//DSCLIENTDATASET bauen
strm := TMemoryStream.Create;
DS_CLIENT.Open;
DS_CLIENT.SaveToStream(strm);
end
else if s = 'getBESTEds' then
...
它说的行: DS_CLIENT.Open 抛出异常:
已引发异常:类 EDatabaseError。 文本:“缺少数据提供者或数据包”。
如上所示,数据提供者已设置为“DS_PROV”,因此它必须是丢失的数据包。
但是,ClientDataSet 不应该从 DataSetProvider 获取数据,而 DataSetProvider 又从 ADOQuery 获取数据,ADOQuery 从数据库获取数据吗?
这是我以我的知识水平所能得到的。 我希望这不是太难,因为在我眼里,我所做的一切都是正确的。
So I'm having this code that processes what the client sends on a pattern. If he sends 'getBENUds', the server sends the DataSet for this table back using the SaveToString method.
Then, this is sent to the client. (I'm using Synapse).
procedure TTCPSocketThrd.Execute;
var s: String;
strm: TMemoryStream;
ADO_CON: TADOConnection;
ADO_QUERY: TADOQuery;
DS_PROV: TDataSetProvider;
DS_CLIENT: TClientDataSet;
begin
CoInitialize(nil);
Sock := TTCPBlockSocket.Create;
try
Sock.Socket := CSock;
Sock.GetSins;
with Sock do
begin
repeat
if terminated then break;
s := RecvTerminated(60000,'|');
if s = 'getBENUds' then
begin
//ini ADO_CON
ADO_CON := TADOConnection.Create(Form1);
ADO_CON.ConnectionString := 'not for public';
ADO_CON.LoginPrompt := false;
ADO_CON.Provider := 'SQLOLEDB.1';
ADO_CON.Open;
//ini ADO_QUERY
ADO_QUERY := TADOQuery.Create(ADO_CON);
ADO_QUERY.Connection := ADO_CON;
//ini DS_PROV
DS_PROV := TDataSetProvider.Create(ADO_CON);
DS_PROV.DataSet := ADO_QUERY;
//ini DS_CLIENT
DS_CLIENT := TClientDataSet.Create(ADO_CON);
DS_CLIENT.ProviderName := 'DS_PROV';
//SQLQUERY Abfrage
ADO_QUERY.SQL.Clear;
ADO_QUERY.SQL.Add('SELECT * FROM BENU');
ADO_QUERY.Open;
//DSCLIENTDATASET bauen
strm := TMemoryStream.Create;
DS_CLIENT.Open;
DS_CLIENT.SaveToStream(strm);
end
else if s = 'getBESTEds' then
...
The line it says: DS_CLIENT.Open an exception is thrown:
An exception has been thrown: class EDatabaseError. Text: 'missing data-provider or data package'.
The data-provider has been set as can be seen above to 'DS_PROV', so it has to be the missing data package.
But shouldn't the ClientDataSet get its data from the DataSetProvider which in turn gets it from the ADOQuery that gets the data from the database?
This is as far as I get with my level of knowledge. I hope its not too difficult, because in my eyes, everything I did was correct.
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在 DS_PROV 创建之后使用
或:(此时你的组件确实没有名称)
Use
or after DS_PROV creation: (at this time your component has really no name)