DateTime格式转换为SQL Server

Question

I am trying to insert into a SQL Server database using a C# application.

In C# I am using datetime.now to get the current datetime:

order.PendingDateTime = DateTime.Now;

This gives me 25/07/2014 11:30:17 .

In the SQL Server table the datatype is datetime . Which holds the data as 2014-07-23 14:54:01.607 for example.

However running the value 25/07/2014 11:30:17 using a normal insert script it inserts into the SQL Server table fine but displays in the table as 2014-07-25 11:30:17 . (This is ok)

However when I use SqlConnection

using (con)
{
   con.Open();
   using (SqlCommand cmd = new SqlCommand())
   {
       cmd.Connection = con;
       cmd.CommandText = @sql;
       cmd.ExecuteScalar();
   }
}

It fails, it says

The conversion of a varchar data type to a datetime data type resulted in an out-of-range value. The statement has been terminated.

I think this is because Visual Studio 2010 and SQL Server uses a different datetime format to each other.

How do I fix this?

Current Code:

string sql = "INSERT INTO Order ([LedgerNumber], [OrderNumber], [OrderDate], [PendingDateTime], [EmailAddress]) VALUES (1, '" + rec.OrderNumber + "', CONVERT(datetime, '" + rec.OrderDate + "', 120), CONVERT(datetime, '" + rec.PendingDateTime + "', 120), '" + rec.EmailAddress + "')";
try
    {
       SqlConnection con2 = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["OrderContext"].ConnectionString);
    using (con2)
        {con2.Open();
         using (SqlCommand cmd = new SqlCommand())
         {
         cmd.Connection = con2;
         cmd.CommandText = @sql;
         cmd.Parameters.AddWithValue("rec.PendingDateTime", DateTime.Now);
         cmd.Parameters.AddWithValue("rec.OrderDate", rec.OrderDate);
         cmd.ExecuteScalar();
         }

Answer 1

Always use sql-parameters instead of string-concatenation. It prevents you from such issues and - more important - from sql-injection:

string sql = @"INSERT INTO Order ([LedgerNumber], [OrderNumber], [OrderDate], [PendingDateTime], [EmailAddress]) 
               VALUES (1, @OrderNumber, @OrderDate, @PendingDateTime, @EmailAddress)";
using (var con = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["OrderContext"].ConnectionString))
using (SqlCommand cmd = new SqlCommand(sql, con))
{
    cmd.Parameters.AddWithValue("@OrderNumber", rec.OrderNumber);
    cmd.Parameters.AddWithValue("@OrderDate", rec.OrderDate);
    cmd.Parameters.AddWithValue("@PendingDateTime", rec.PendingDateTime);
    cmd.Parameters.AddWithValue("@EmailAddress", rec.EmailAddress);
    con.Open();
    cmd.ExecuteNonQuery(); 
}

You: " if I wasn't using datetime.now and get a datetime from a value entered by user. Say '24/07/2014 10:30' how do I use the AddWithValue to achieve this? "

You have to parse the input to DateTime first. Therefore use DateTime.Parse or DateTime.TryParse , DateTime.ParseExact or DateTime.TryParseExact . The TryParse -methods enable you to check if the input is a valid DateTime .

For example:

DateTime pendingDateTime;
if(!DateTime.TryParse(TxtPendingDateTime.Text, out pendingDateTime))
{
    MessageBox.Show("Please enter a valid Pending-Date in the format: yourformat");
    return;
}
// here you can go on with the code above