cmd.Parameters.AddWithValue("@param1",param1 ?? DbNull.Value)

Question

I have int? type value which can be either null or have some value. I want to execute a insert statement using parametrized query to insert accordingly.

int? val1=null; 
SqlCeCommand cmd;
string insert = "insert into table(col1)values(@col_1)";
cmd = new SqlCeCommand();
cmd.CommandText = insert;
cmd.Parameters.AddWithValue("@col_1", val1 ?? Convert.ToInt32(DBNull.Value)));
cmd.Connection = cn1;
cn1.Open();
cmd.ExecuteNonQuery();
cn1.Close();

This code throws format exception error. I even tried

cmd.Parameters.AddWithValue("@col_1", (!val1.HasValue) ? val1 : Convert.ToInt32(DBNull.Value));

How shld it b done?

Answer 1

no need to convert if null set DBNull

cmd.Parameters.AddWithValue("@col_1", (object)val1 ??DBNull.Value);

Answer 2

I would believe that changing the line to the following should work:

cmd.Parameters.AddWithValue("@col_1", val1 ?? DBNull.Value);

Since this would set the parameter value to an object type.

If that fails for some reason try to cast the result to an object like this:

cmd.Parameters.AddWithValue("@col_1", (object)(val1 ?? DBNull.Value));

But this should not be necessary.

Edit: Actually, this should work:

cmd.Parameters.AddWithValue("@col_1", val1 ?? (object)DBNull.Value);

Answer 3

You Should change add parameter code like this:

if (val1.HasValue)
{
    cmd.Parameters.AddWithValue("@col_1", val1.Value);
}
else
{
    cmd.Parameters.AddWithValue("@col_1", DBNull.Value);
}