String was not recognized as a valid DateTime

Question

My code is:

 protected void Page_Load(object sender, EventArgs e)
    {
        string myDate = Request.QueryString["period"];
        if (!String.IsNullOrEmpty(myDate))
        {
            myDate = myDate.Replace("!", ":");
        }
        DateTime dt1 = Convert.ToDateTime(myDate);
        DateTime dt2 = DateTime.Now;
        TimeSpan variable = dt2 - dt1;
        if (variable.TotalMinutes > 5)
        {
            Response.Write("Download time is expired now");
        }
        else
        {
            Response.Redirect("Default.aspx", false);
        }



    }

and I'm getting error like:

String was not recognized as a valid DateTime.

Answer 1

Try with DateTime.ParseExact() method;

Converts the specified string representation of a date and time to its DateTime equivalent using the specified format and culture-specific format information. The format of the string representation must match the specified format exactly.

DateTime date = DateTime.ParseExact(myDate, "dd/MM/yyyy hh:mm:ss tt", CultureInfo.InvariantCulture);

Here is a DEMO .

You can check more Custom Date formats from Custom Date and Time Format Strings

Answer 2

Use DateTime.ParseExact

since you have this date formatted like 09/04/2013 10:41:45 AM

DateTime dt1 = DateTime.ParseExact(myDate, "MM/dd/yyyy hh:mm:ss tt", 
                                           CultureInfo.InvariantCulture)

if 09 is day, change the pattern into dd/MM/yyyy hh:mm:ss tt

For more information about Date and Time Format Strings,

• Custom Date and Time Format Strings