deleting sqlserver table data with delete command using DataAdapter in c#

[C# Programming]

Hi,
I am trying to insert/update/delete a field from my sql server table using dataadapter in c# windows application.

Here insert and update are happening,but 'delete' is not working

I will show my delete part :

public int UpdateAllUserDetails(DataSet dsUsers)
{
private SqlConnection connection;
private SqlCommand command;
private SqlDataAdapter dataAdapter;

connection = new SqlConnection(ConfigurationManager.AppSettings.Get("conString"));
connection.Open();
dataAdapter = new SqlDataAdapter(command);

dataAdapter.DeleteCommand = new SqlCommand("DELETE FROM UserDetails WHERE vUserName=@vUserName", connection);
dataAdapter.DeleteCommand.Parameters.Add("@vUserName", SqlDbType.VarChar, 50, "vUserName");

int ret = dataAdapter.Update(dsUsers);
return ret;

}

can somebody say what is missing here?