C# SQL Data Adapter System.Data.StrongTypingException

c# sql ado.net dataset dataadapter
René Stalder picture René Stalder · Apr 23, 2010 · Viewed 9k times · Source

I get my data from SQL to Dataset with Fill. It's just one table with two columns (CategoryId (int) and CategoryName (varchar)).

When I look at my dataset after fill method, CategoryId Columns seems to be correct. But in the CategoryName I have a System.Data.StrongTypingException.

What could that mean?

Any Ideas?

Answer

Julian de Wit picture Julian de Wit · Apr 29, 2010

When you get the value of a row/column in a typed dataset, by default it raises this exception when the value is DBNull. So

string x = Row.CategoryName;//Raises this exception when CategoryName is null.

You can correct this with the typed dataset designer.
Set the property "Nullvalue" of the CategroyName column to "(Empty)"

Related questions

How to fill Dataset with multiple tables?

I'm trying to fill DataSet which contains 2 tables with one to many relationship. I'm using DataReader to achieve this : public DataSet SelectOne(int id) { DataSet result = new DataSet(); using (DbCommand command = Connection.CreateCommand()) { command.CommandText = "select * from table1"; var param = …

Read More
Update DataSet structure in Visual Studio to match new SQL Database Structure

After making some changes to my SQL database structure (using scripts in SQL Server Management Studio), how can I update my DataSet.xsd file in Visual Studio to match the new structure? Must I do this manually? I considered deleting …

Read More
How do I extract data from a DataTable?

I have a DataTable that is filled in from an SQL query to a local database, but I don't know how to extract data from it. Main method (in test program): static void Main(string[] args) { const string connectionString = "server=…

Read More