c# - LINQ to Entities 无法识别方法 'Int32 ToInt32(System.String)' 方法，并且无法将此方法翻译成存储表达式

Question

当我尝试这段代码时出现这个错误:

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，您需要先在 LINQ 之外解析为 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);