错误：在C＃4中无法将字符串识别为有效的DateTime（格式）

Question

I have a datepicker in my c# application that provide strings like these:

"2016/1/1"

"2016/11/15"

But I want to change them to these formats:

"2016/01/01"

"2016/11/15"

I use this code:

    string searchstring = " and ProductStartDate Between '" + 
    String.Format("{0:yyyy/MM/dd}", Convert.ToDateTime(calender_from.Text)) + 
    "' and '" + 
    String.Format("{0:yyyy/MM/dd}", Convert.ToDateTime(calender_to.Text)) + "'";

but when I run following error occurs :

An unhandled exception of type 'System.FormatException' occurred in mscorlib.dll

Additional information: String was not recognized as a valid DateTime.

Any idea?

Answer 1

Use DateTime.ParseExact instead of Convert.ToDateTime :

calender_from.Text = "2016/1/1";

DateTime date = DateTime.ParseExact(calender_from.Text, "yyyy/M/d", null);

Then you can do this:

string searchstring = " and ProductStartDate Between '" + String.Format("{0:yyyy/MM/dd}", date) + ...