Object cannot be cast from DBNull to other types

I am trying to convert DateTime after retrieving a row using stored proceduce as follows

        //get single product
        public Product GetProduct(int ProductID)
        {
            StringBuilder sql = new StringBuilder();
            sql.Append("usp_SelectProduct");
            SqlParameter[] p = new SqlParameter[1];
            p[0] = new SqlParameter("@P_Productid", SqlDbType.Int);
            p[0].Value = ProductID;
            DataRow row = Db.GetDataRow(sql.ToString(), p);
            int productid = int.Parse(row["P_ProductID"].ToString());
              ...
            decimal  Reorderlevel = decimal.Parse(row["P_ReorderLevel"].ToString());
            string  Warehouseno = row["P_WareHouseNo"].ToString();
            DateTime  Modifieddate = Convert.ToDateTime(row["P_ModifiedDate"]);
            string Memo = row["P_Memo"].ToString();
            string Desc = row["P_Desc"].ToString();
            Product product;
            return product = new Product(productid, Productname, Qtyperunit, Unitprice, Unitsinstock, Unitsonorder, Reorderlevel, Warehouseno, Modifieddate, Memo, Desc);
        }

but I get an error saying:

===============================================================================================================================
Object cannot be cast from DBNull to other types.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.InvalidCastException: Object cannot be cast from DBNull to other types.

Source Error:


Line 103:            decimal  Reorderlevel = decimal.Parse(row["P_ReorderLevel"].ToString());
Line 104:            string  Warehouseno = row["P_WareHouseNo"].ToString();
Line 105:             DateTime  Modifieddate = Convert.ToDateTime(row["P_ModifiedDate"]);
Line 106:            string Memo = row["P_Memo"].ToString();
Line 107:            string Desc = row["P_Desc"].ToString();
 

Source File: C:\IList_WareHouse_Solution\DataObjects\SqlServer\SqlServerProductDao.cs    Line: 105
===============================================================================================================================

then I tried the following:

            object Modifieddate_obj = row["P_ModifiedDate"];
            if (Modifieddate_obj != System.DBNull.Value)
            {
                Modifieddate = Convert.ToDateTime();
            }

but that doesn't work either.  I don't know how to deal with this DateTime.  The current contains the value {}.   Can I return 00/00/00 00:00:00 if datetime is blank?  This Modifieddate is going to be displayed in detailsview control.

thanks
Nick
LVL 1
countyprobSystem AnalystAsked:
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

x
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

bramsquadCommented:
Modifieddate = Convert.ToDateTime(Modifieddate_obj);

~b
0
countyprobSystem AnalystAuthor Commented:
Ok I tried that but now I get:

Error      11      Use of unassigned local variable 'Modifieddate'      C:\IList_WareHouse_Solution\DataObjects\SqlServer\SqlServerProductDao.cs      119      144      DataObjects


it is having a problem with variable in my return statement


           string  Warehouseno = row["P_WareHouseNo"].ToString();
            DateTime Modifieddate;
            object Modifieddate_obj = row["P_ModifiedDate"];
            if (Modifieddate_obj != System.DBNull.Value)
            {
                Modifieddate = Convert.ToDateTime(Modifieddate_obj);
            }
            string Memo = row["P_Memo"].ToString();
            string Desc = row["P_Desc"].ToString();
            Product product;
            return product = new Product(productid, Productname, Qtyperunit, Unitprice, Unitsinstock, Unitsonorder, Reorderlevel, Warehouseno, Modifieddate, Memo, Desc);

Why would it complain if I already defined Modifieddate as DateTime type?

nick
0
bramsquadCommented:
the reason is becuase when you return you include the variable 'Modifieddate' however, you only assign a value to it when 'Modifieddate_obj' is not equal to null.   So when it is null and you dont assign a value to it, itll give that error.

So you have to make sure you assign a value to the variable.  Just do it at declaration.

DateTime Modifieddate = DateTime.MinValue;

this will set it to the min value (1/1/0001 12:00:00 AM)

this way you can always check for that and act accordingly

~b
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
Exploring SQL Server 2016: Fundamentals

Learn the fundamentals of Microsoft SQL Server, a relational database management system that stores and retrieves data when requested by other software applications.

rameedevCommented:
Can you try checking for a simple null something like this

DateTime Modifieddate;
if(!row["P_ModifiedDate"]==null)
{
    Modifieddate = Convert.ToDateTime(Modifieddate_obj);
}
0
Gautham JanardhanCommented:
string  Warehouseno = row["P_WareHouseNo"].ToString();
                  DateTime Modifieddate = Datetime.MinValue;
                  
                  if (!row.IsNull("P_ModifiedDate"))
                  {
                        Modifieddate = Convert.ToDateTime(Modifieddate_obj);
                  }
                  string Memo = row["P_Memo"].ToString();
                  string Desc = row["P_Desc"].ToString();
                  return new Product(productid, Productname, Qtyperunit, Unitprice, Unitsinstock, Unitsonorder, Reorderlevel, Warehouseno, Modifieddate, Memo, Desc);
0
Gautham JanardhanCommented:
assuming row is DataRow
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
C#

From novice to tech pro — start learning today.