Data Loading in datagrid is too slow

Hi All My Friends

I Connect to DB (Oracle) and execute a select Command (From table that has very records for example 1000000 records) then load in DataGrid in C sharp.it does successfully but very very slowly.

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DataSet ds = new DataSet();

String constr             = p_ConnectionStr;

String CommandStr ="SELECT * FROM MTL_SYSTEM_ITEMS";

System.Data.OracleClient.OracleConnection ConOracle = new System.Data.OracleClient.OracleConnection(constr);

System.Data.OracleClient.OracleCommand ComOracle = new System.Data.OracleClient.OracleCommand(CommandStr, ConOracle);

System.Data.OracleClient.OracleDataAdapter AdpOracle = new System.Data.OracleClient.OracleDataAdapter(CommandStr, ConOracle);

ConOracle.Open();
ComOracle.ExecuteScalar();
AdpOracle.Fill(ds, "MTL_SYSTEM_ITEMS");
ConOracle.Close();

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Please Help Me to Find Solutions for solve the Problem.

Best Regards

BABAK