Question

I’m pulling date values out of mysql and displaying them in locally used format. See below:

I have this datetime value 2012-11-01 08:00:00 … yyyy-MM-dd HH:mm:ss

I need this to appear as 01-11-2012 08:00:00 … dd-MM-yyyy HH:mm:ss

I can do this simply enough as follows:

Dim dr As MySqlDataReader = cmd.ExecuteReader(sql)

If dr.Read()
    Dim mydate As DateTime = dr("date_column")

    txtDate.Text = mydate.ToString("dd-MM-yyyy") & " " & mydate.ToString("HH:mm:ss")
End If

This works well enough, but my problem is that if I want to update the record from this textbox, I can’t use this format for the date because mysql complains about an error (object out of range or something).

So what I need to do now is to convert this back to yyyy-MM-dd. The difficulty here is that .NET will automatically assume my dd value should be the MM value and vice versa.

This results in a value of 01-11-2012 writing into the database as 11-01-2012.

How can I reformat the date for insert/update into the database while maintaining the integrity of the date that’s being used here?

Thanks in advance

Answer 1

Use a parameterized query for the update:

query = "UPDATE SomeTable SET date_column = @newDate WHERE record_id = @record_id"
conn = new SqlConnection("my connection string")

cmd = new SqlCommand(query, conn)
cmd.Parameters.Add("newDate", SqlDbType.DateTime).Value = new Date(txtDate.Text)
cmd.Parameters.Add("record_id", SqlDbType.Int).Value = record_id

'Rest of code to execute cmd

If that doesn’t parse the date from the TextBox correct, parse it beforehand with:

Date.ParseExact(txtDate.Text, "dd-MM-yyyy HH:mm:ss", CultureInfo.InvariantCulture)

Also, the line:

txtDate.Text = mydate.ToString("dd-MM-yyyy") & " " & mydate.ToString("HH:mm:ss")

could also be written as:

txtDate.Text = mydate.ToString("dd-MM-yyyy HH:mm:ss")

which might be easier to read.