Question

I have a web forms application which allows to update database columns. One of the database columns is Finish Date which is of date datatype in the SQL Server database.

I use SQL query with parameters and textbox to provide the new value for the finish date.

This is a code which gets me the value of the date from a text box within the grid:

TextBox tFD = (TextBox)grdProjectUpdate.Rows[e.RowIndex].Cells[11].FindControl("proFDTextBox");

then I use a parameter:

cmd.Parameters.Add("@proFD", SqlDbType.Date).Value = tFD.Text.Trim();

to update the value using this SQL statement:

UPDATE PMSprojects SET proFD = @proFD ,...    

This solution works fine whenever there is an actual date provided. However, it does not save nulls. If I provide an empty string, it is being converted into 1900-01-01 date, even though the column in the database allows nulls.

How could I solve this issue and save null to the database?

Answer 1

You have to write code around this to handle, and pass DbNull.Value when the value is null.

cmd.Parameters.Add("@proFD", SqlDbType.Date).Value = (tFD.Text.Trim().Length > 0) ? (object)tFD.Text.Trim() : DbNull.Value;