Updating a datarow in dataset

Im trying to update a data row in a data set but my program keeps on crashing at this one line, i was wandering if someone could help me out with the problem

heres the code

Code:

---


void updateDB()
                {       
                        for(int i=0; i < export_log.Tables[0].Rows.Count; i++)
                        {
                               
                                export_log.Tables[0].Rows[i]["export_id"] = 9999;
                                dc.updateDataRow(export_log.Tables[0].Rows[i]);
                        }

                }


        public void updateDataRow(DataRow dr)
                {



                        try
                        {

                                string table = "ExportLog";
                                String query = "select * from " + table;
                                DataSet ds = new DataSet();
                                SqlDataAdapter da = new SqlDataAdapter();

                                SqlCmd.CommandText = query;
                                SqlCmd.Connection = ObjConn;
                       
                                SqlCommandBuilder builder = new SqlCommandBuilder(da);
                                da.MissingSchemaAction = MissingSchemaAction.AddWithKey;

                                       
ds.Tables[table].Rows.Add(dr); // code crashes here because of null exception
                                da.Fill(ds);
               
                                da.Update(ds,table);
                        }
                        catch(SqlException ex)
                        {
                                Console.WriteLine("Database error");
                        }

                }

---

Additional information: Object reference not set to an instance of an object.

Thats the error i get when I use the debugger.

this is the error i get when i check the debugger:

Additional information: Object reference not set to an instance of an object.

My guess ( since there´s little information given ) :

Code:

---

DataSet ds = new DataSet();
ds.Tables[table].Rows.Add(dr);

---

Are you sure there are Tables in the object ds ?

My second guess is:

Code:

---

public void updateDataRow(DataRow dr)
ds.Tables[table].Rows.Add(dr);

---

Are you sure that the Datarow object that is being passed as a parameter ( in updateDateRow signature ) is actually referencing to something ?

A quick way to check these things is to do something like

Code:

---

public void updateDataRow(DataRow dr) {
  if(dr.Equals(null)) {
        Console.WriteLine("dr -> null");
  }
  //rest of code goes here.
}

---