if (dr.Read())
{
if (dr.IsDBNull(0))
{
return null;
}
else
{
region = (String)dr["region"];
}
}
else
{
// do something else as the result set is empty
}
Have trouble reading a null returned from stored procedure
-
04-07-2023 - |
문제
I have a stored procedure that returns a single record, either null
or data if present.
In my code I need to check what that procedure returns. What is the right way to do it?
Now when, running the code I have an exception saying: "Invalid attempt to read when no data is present." I'm using Visual Studio 2005.
Here is my method:
public static String GetRegionBasedOnIso(String isoNum)
{
SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["MyConn"].ConnectionString);
String region = null;
try
{
using (SqlCommand cmd = new SqlCommand("MyProc", conn))
{
conn.Open();
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.AddWithValue("@isoNum", isoNum);
using (SqlDataReader dr = cmd.ExecuteReader())
{
if (dr.IsDBNull(0))
{
return null;
}
else
{
region = (String)dr["region"];
}
}
}
}
catch (Exception e)
{
throw new System.Exception(e.Message.ToString());
}
finally
{
conn.Close();
}
return region;
}
What can I do to fix it? Thank you
해결책
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