Object cannot be cast from DBNull to other types

Question

I am getting an error "Object cannot be cast from DBNull to other types" Please help me i am new to this

public void GridView1_SelectedIndexChanged(object sender, EventArgs e)
    {
   int count = 0;
        SqlConnection con = new SqlConnection("server=ADMIN- PC\\SQLEXPRESS;initial catalog=content;integrated security=true");
        con.Open();
        SqlCommand cmd;
        cmd = new SqlCommand("select * from usrimg where ImageName='" + GridView1.SelectedDataKey["ImageName"].ToString() + "'", con);
        SqlDataReader dr = cmd.ExecuteReader();
        if (dr.Read())
        {

            count = Convert.ToInt16(dr[4]);//Error:Object cannot be cast from DBNull to other types 
            count++;
            dr.Close();
            cmd = new SqlCommand("update usrimg set [count] =" + count + "where ImageName='" + GridView1.SelectedDataKey["Image Name"].ToString() + ")", con);
            cmd.ExecuteNonQuery();
            con.Close();
        }

Related: http://stackoverflow.com/questions/6098646/object-cannot-be-cast-from-dbnull-to-other-types — Soner Gönül, Apr 06 '15 at 07:12
Try google error rather than posting, this is a very common mistake & lots of posts about it — Shubhojit, Apr 06 '15 at 07:14
I tried searching. But it didnt work.. Can you please help me out with this — Career, Apr 06 '15 at 07:19

score 1 · Answer 1 · answered Apr 07 '15 at 19:57

1

I believe you have a null value in that position in your table. Try making sure it's not null before you try to convert it.

if(!Convert.IsDBNull(dr[4]))
{
count = Convert.ToInt16(dr[4]);
//whatever you need done with the count in here...
}

answered Apr 07 '15 at 19:57

Wendy E

99
4

Object cannot be cast from DBNull to other types

1 Answers1