SQL Server 2008(版本10.50.2550)。如何從SqlDataReader獲得Guid uniqueidentifier
我有一個select查詢來返回uniqueidentifier類型的單個列。
我想把它變成一個類型爲Guid的C#變量。
以下所有方法都會導致異常。
閱讀器是SqlDataReader類型。
using (var reader = command.ExecuteReader())
{
if (reader.Read())
{
Guid guid = reader.GetGuid(reader.GetOrdinal("integ_schemehistoryId")); //1
Guid guid = Guid.Parse((string)reader["integ_schemehistoryId"]); //2
Guid guid = (Guid)reader["integ_schemehistoryId"]; //3
Guid guid = new Guid((string)reader["integ_schemehistoryId"]); //4
Guid guid = Guid.Parse(reader["integ_schemehistoryId"].ToString()); //5
}
}
錯誤1:
System.Data.SqlClient.SqlException (0x80131904): Conversion failed when converting from a character string to uniqueidentifier.
at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection)
at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection)
at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning()
at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj)
at System.Data.SqlClient.SqlDataReader.HasMoreRows()
at System.Data.SqlClient.SqlDataReader.ReadInternal(Boolean setTimeout)
at System.Data.SqlClient.SqlDataReader.Read()
at Simego.DataSync.DynamicColumns.DataSourceRowOverride.get_EpochSchemeHistoryID()
錯誤2:
System.InvalidCastException: Unable to cast object of type 'System.Guid' to type 'System.String'.
at Simego.DataSync.DynamicColumns.DataSourceRowOverride.get_EpochSchemeHistoryID()
錯誤3:
System.Data.SqlClient.SqlException (0x80131904): Conversion failed when converting from a character string to uniqueidentifier.
at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection)
at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection)
at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning()
at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj)
at System.Data.SqlClient.SqlDataReader.HasMoreRows()
at System.Data.SqlClient.SqlDataReader.ReadInternal(Boolean setTimeout)
at System.Data.SqlClient.SqlDataReader.Read()
at Simego.DataSync.DynamicColumns.DataSourceRowOverride.get_EpochSchemeHistoryID()
錯誤4:
System.InvalidCastException: Unable to cast object of type 'System.Guid' to type 'System.String'.
at Simego.DataSync.DynamicColumns.DataSourceRowOverride.get_EpochSchemeHistoryID()
錯誤5:
System.Data.SqlClient.SqlException (0x80131904): Conversion failed when converting from a character string to uniqueidentifier.
at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection)
at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection)
at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning()
at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj)
at System.Data.SqlClient.SqlDataReader.HasMoreRows()
at System.Data.SqlClient.SqlDataReader.ReadInternal(Boolean setTimeout)
at System.Data.SqlClient.SqlDataReader.Read()
at Simego.DataSync.DynamicColumns.DataSourceRowOverride.get_EpochSchemeHistoryID()
你會得到什麼錯誤? – SLaks
'GetGuid'應該可以工作。我會建議*反對任何不必要地執行兩個字符串轉換的方法。請提供調用'GetGuid'時出現的錯誤的詳細信息。 –
@JonSkeet哪一個呢? – cja