Issue to date time field

Question

Hi,
I get the issue below

String was not recognized as a valid DateTime. at System.DateTimeParse.ParseExact(String s, String format, DateTimeFormatInfo dtfi, DateTimeStyles style)

When I have the value like

7/1/2021 12:00:00 AM

to the field.

Here is of the code the line leading to the issue.

Answer 1

I would recommend using DateTime.TryParse to ensure there is a proper DateTime.

Get user input, assert text is a DateTime and if so pass to a method, in this case in the second code block the data operation is inserting a new record but the same applies for updates too.

if (DateTime.TryParse(TextBox1.Text.Trim(), out var dateTime))  
{  
    var (success, exception, id) = DataOperations.AddNewRecord(dateTime);  
    if (success)  
    {  
        // we can use id var  
    }  
    else  
    {  
        // failure - log error using exception var about  
    }  
}  
else  
{  
    // not a valid date time, tell the user  
}  

Backend code

public class DataOperations  
{  
  
	private static string _connectionString =  
		"Data Source=.\\sqlexpress;Initial Catalog=Examples;Integrated Security=True";  
  
	public static (bool success, Exception exception, int id) AddNewRecord(DateTime dateTime)  
	{  
		using var cn = new SqlConnection { ConnectionString = _connectionString };  
		using var cmd = new SqlCommand { Connection = cn };  
		cmd.CommandText = "INSERT INTO dbo.Table1 (SomeDateTime) " +  
						  "VALUES (@SomeDateTime);" +  
						  "SELECT CAST(scope_identity() AS int);";  
  
		cmd.Parameters.Add("@SomeDateTime", SqlDbType.DateTime).Value = dateTime;  
  
		try  
		{  
			cn.Open();  
			return (true, null, Convert.ToInt32(cmd.ExecuteScalar()));  
  
		}  
		catch (Exception ex)  
		{  
			return (false, ex, -1);  
		}  
	}  
}  

Answer 2

ParseExact would be expecting a leading 0 on dd/MM. try d/M/yyyy.

Answer 3

Hi @Peter_1985 ,

String was not recognized as a valid DateTime

As the error says, the string is not a valid datetime.
Your format string is missing the time format and AM/PM deisgnator, and the day and month are reversed and the numbers don't match.
The correct one should be: M/d/yyyy hh:mm:ss tt

 //String = "7/1/2021 12:00:00 AM";    
cmd3.Parameters.Add("@vaild_from", SqlDbType.DateTime).Value = DateTime.ParseExact(TextBox1.Text.Trim(), "M/d/yyyy hh:mm:ss tt", CultureInfo.InvariantCulture);  
    //String = "07/01/2021 12:00:00 AM";    
cmd3.Parameters.Add("@vaild_from", SqlDbType.DateTime).Value = DateTime.ParseExact(TextBox1.Text.Trim(), "MM/dd/yyyy hh:mm:ss tt", CultureInfo.InvariantCulture);  

Best regards,
Lan Huang

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