c# - 有没有办法在 C# 中测试特定的 sql 异常类型？

Question

从数据库中删除记录时，偶尔会遇到引用约束异常。

这里是异常的详细信息。当异常与外键约束错误具体相关时，是否可以向用户显示消息？

我可以查看异常错误字符串并测试单词是否存在，但我不确定是否有更好的方法来检查特定的 SQL 错误。

谢谢 凯文

Message: The DELETE statement conflicted with the REFERENCE constraint "FK_Customers_PaymentTerms". The conflict occurred in database "kd", table "dbo.Customers", column 'CstPtmID'.
The statement has been terminated.
Source: .Net SqlClient Data Provider
TargetSite: Void OnError(System.Data.SqlClient.SqlException, Boolean)
StackTrace:    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.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString)
   at System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async)
   at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, DbAsyncResult result)
   at System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(DbAsyncResult result, String methodName, Boolean sendToPipe)
   at System.Data.SqlClient.SqlCommand.ExecuteNonQuery()
   at System.Data.Mapping.Update.Internal.DynamicUpdateCommand.Execute(UpdateTranslator translator, EntityConnection connection, Dictionary`2 identifierValues, List`1 generatedValues)
   at System.Data.Mapping.Update.Internal.UpdateTranslator.Update(IEntityStateManager stateManager, IEntityAdapter adapter)

Answer 1

Is it possible to display a message to the user when the exception is specifically related to a foreign key constraint error?

是的，您可以检查 Number SqlException 的:

try
{
    // do your database query
}
catch (SqlException ex)
{
    if (ex.Number == .....)
    {
        // Can't remember from the top of my head the exact error code 
        // that is triggered in this situation. Just check it.
    }
}

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如评论部分所述，最好检查 Errors数组，因为可能存在与单个 SQL 查询相关的多个错误。