Handle null values

Question

I have a command that display the Name based on EmpID:

using (SqlCommand SqlCommand = new SqlCommand("Select EmpID, Name from EmpTable where EmpID = @a", myDatabaseConnection))
                {
                    SqlCommand.Parameters.AddWithValue("@a", textBox1.Text);
                    using (SqlDataReader sqlreader = SqlCommand.ExecuteReader())
                    {

                        if (sqlreader.Read())
                        {
                            Namelabel.Text = sqlreader.GetString(sqlreader.GetOrdinal("Name"));
                        }
                    }
                }

How I will handle if name data is null? Like if data is null Namelabel.Text = "".

What is there to handle? I would imagine the code you already have would work just fine if the output is null. — Servy
– Servy, Commented Jul 22, 2013 at 18:29

Karl Anderson · Accepted Answer · 2013-07-22 18:32:50Z

1

Do you mean something like this?

Namelabel.Text = !String.IsNullOrEmpty(sqlreader.GetString(sqlreader.GetOrdinal("Name"))) ? sqlreader.GetString(sqlreader.GetOrdinal("Name")) : "Value not found";

This will give some output if the value in the database is NULL.

answered Jul 22, 2013 at 18:32

Karl Anderson

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David · Accepted Answer · 2013-07-22 18:39:22Z

1

You can use IsDBNull() to check for a null value before trying to read that value as a string. Something like this:

if (sqlreader.Read())
{
    var columnOrdinal = sqlreader.GetOrdinal("Name");
    if (sqlReader.IsDBNull(columnOrdinal))
        NameLabel.Text = string.Empty;
    else
        Namelabel.Text = sqlreader.GetString(columnOrdinal);
}

answered Jul 22, 2013 at 18:39

David

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Comments

Nigel B · Accepted Answer · 2013-07-22 18:32:16Z

0

Just test for null as you read.

 if (sqlreader.Read())
 {
      Namelabel.Text = sqlreader.GetString(sqlreader.GetOrdinal("Name")==null?"":sqlreader.GetOrdinal("Name"));
 }

answered Jul 22, 2013 at 18:32

Nigel B

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