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c#sqlsqldatareaderdatareader

Handle NULL in Datareader


This is the code I' using for reading data from sql through DataReader. It gives Error when there is a NULL in table. How to handle it?

I tried

c.ActualWeight= dr[0] as float? ?? default(float);

The problem with this is that it is successful in Handling NULLs but the result is Always 0 even if the sql database has value 1 in that field.

{ 
    List<Inventory_Connector> LC = new List<Inventory_Connector>();
    string ConString = "data source=DELL\\SQLSERVER1;Initial Catalog=Camo;Integrated Security=True";
    SqlConnection con = new SqlConnection(ConString);
    SqlCommand cmd = new SqlCommand("Select Top 17 * from Inventory_Connector", con);
    con.Open();
    SqlDataReader dr = cmd.ExecuteReader();

    while (dr.Read())
    {
        c.ActualWeight = float.Parse(dr[0].ToString().Trim());
    }

    LC.Add(c);
}

dr.Close();
con.Close();
return LC;

Solution

  • You can use SqlDataReader.IsDBNull to check for null values out of a data reader. C# null and DBNull are different.

     c.ActualWeight = 
         dr.IsDBNull(0) 
         ? default(float) 
         : float.Parse(dr[0].ToString().Trim());