CODEWITHSUNDEEP
c#
user2684131
user2684131

Reputation: 147

Object reference not set to an instance of an object in c# how to check for null value?

I am getting nullrefernce exception after running c# code at this line 

  var data = info.details.Split('|');

c# code:

 public studentinfo SaveData(studentinfo info)
        {
            bool returnBool=false;
            SqlConnection con;

                var data = info.details.Split('|');


                var response = new studentinfo
                {
                    ID = data[0],
                    Name = data[1],
                    Project = data[2],
                    Result = data[3]
                };


            con = new SqlConnection(ConfigurationManager.ConnectionStrings["Myproject.Properties.Settings.MyConnection"].ConnectionString);

            string sqlStr = "INSERT INTO Result (ID,Name,Project,Result) values('" + data[0] + "', '" + data[1] + "', '" + data[2] + "', '" + data[3] + "')";
            SqlCommand dbCommand = new SqlCommand(sqlStr, con);

             try
            {
                con.Open();
                if (dbCommand.ExecuteNonQuery() != 0)
                {
                    returnBool = true;
                }

                if (!data.Equals(null))
                {
                    returnBool = true;
                }
                con.Close();
            }
            catch
            {
               returnBool= false;
            }
             con.Close();
             return response;

        }

I tried to implement:

if (!data.Equals(null))
            {
                returnBool = true;
            }

but even then its giving the same object reference exception, Please help me to resolve it. Thanks

Upvotes: 0

Views: 18448

Answers (4)

Ahmed Rabie
Ahmed Rabie

Reputation: 27

using C# last version

if(data is not null)
{

}

Note that "== null" and "!= null" doesn't work for null reference

Upvotes: -1

X3074861X
X3074861X

Reputation: 3819

You need to check for null before you try the string split 

if (info == null)
{
    // do not attempt to split details, maybe throw something here
}

However, you may want to look at how that SaveData(studentinfo info) is being called, and under what circumstances would it be passed a null studentinfo object.

Upvotes: 0

Sriram Sakthivel
Sriram Sakthivel

Reputation: 73442

Try this

if(data != null)
{

}

Or

if(object.ReferenceEquals(data,null))
{

}

Probably as @zigdawgydawg pointed out exception will not be in checking data because string.Split will never return null. So, you need to avoid null parameter.

if(info==null || info.details == null)
{
    return null;//Or throw new ArgumentException();
}

Upvotes: 9

zigdawgydawg
zigdawgydawg

Reputation: 2046

The Null reference exception is because either info or info.details is null. You'll need to check for nulls before you do a Split.

Upvotes: 2

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