c# - 如何在企业库中的 DbCommand 上传递 MySQL 空参数

Question

我试图在下面的代码中为第一个参数传递一个空值，但 MySQL 提示

Incorrect number of arguments for PROCEDURE myProc; expected 2, got 1

When I manually call the procedure with the first argument as null, it works, but when EmptyAsNullStartsWith(employeeNumberText.Text) returns null, it complains.

Database db = DatabaseFactory.CreateDatabase(
  ConfigurationManager.AppSettings["dbType"]
);
DbCommand cmd = db.GetStoredProcCommand("staff_listforinquiry");
db.AddeParameter(
  cmd, 
  "in_employeeNumber", 
  DbType.String, 
  EmptyAsNullStartsWith(employeeNumberText.Text)
);
db.AddeParameter(
  cmd, 
  "in_name", 
  DbType.String, 
  EmptyAsNullContains(employeeNameText.Text)
);

Answer 1

您是否尝试过让 EmptyAsNullContains(employeeNameText.Text) 返回 DBNull 而不是常规 null？