LINQ to Entities无法识别方法'Int32 ToInt32（System.String）'方法，并且此方法无法转换为存储表达式

Question

尝试此代码时出现此错误：

TaxiEntities db = new TaxiEntities();
bool IsUserPassCorrected = db.tblOperators.Any(item => item.UserName.ToLower() == txtUserName.Text.ToLower() &&
item.Password == Convert.ToInt32(txtPassWord.Text));

if (!IsUserPassCorrected)
{
    MessageBox.Show("Username or Password is incorrected! Please try again");
}

Answer 1

由于LINQ to Entities不支持Convert.ToInt32，因此您需要先在LINQ之外解析int：

TaxiEntities db = new TaxiEntities();
int password = int.Parse(txtPassWord.Text);

bool IsUserPassCorrected = db.tblOperators
            .Any(item => item.UserName.ToLower() == txtUserName.Text.ToLower() 
                      && item.Password == password);