LINQ to Entities無法識別方法'Int32 ToInt32（System.String）'方法，並且此方法無法轉換為存儲表達式

Question

我在嘗試此代碼時遇到此錯誤：

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

由於LINQ to Entities不支持Convert.ToInt32 ，因此需要先在LINQ之外解析為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);