No, it certainly isn't a spelling mistake. And the error is telling
you exactly where the problem lies... ;-)
The DataRow class exposes its Columns in the Row by means of the
Indexer, i.e., the default Item property. This means that you can
retrieve the data within any column in a given DataRow by the
following syntax (in addition to various overloads) :
---
Dim myData as Object = myDataRow.Item("MyColumnName")
---
And the relevant part of your code is :
---
objRow.Item(strSurname + ", " + strFirstName)
---
What your code is trying to do is to find the data in the column named
"Clancy, Martina" because that parameter is meant for the column name.
It appears to me that you should simply write the following statement
because you already have the firstName and lastName values in
variables:
---
lstStudents51.Items.Add(strSurname + ", " + strFirstName)
---
P.S.: Since you are at the learning stage, I won't tell you that the
first line in your For-loop should probably be outside the loop (if
not removed altogether) because it serves no purpose within. Or maybe
I will ! ;-)
HTH.
On Jan 19, 6:43 pm, Laura <[email protected]> wrote:
> I have now made changes to my project. Now I have one form where you
> select a class from a combobox and then the listbox needs to be
> populated with the students from the selected class. However, I keep
> getting an error and cannot figure out what's up ( my coding abilities
> are not the strongest - as you may have noticed).
>
> Public Sub FillStudentList()
> Dim j As Integer
> Dim strSurname As String
> Dim strFirstName As String
>
> For j = 1 To objDataSet.Tables("tblStudent").Rows.Count
> objRow = objDataSet.Tables("tblStudent").Rows.Find
> (cboClassSelect.SelectedValue.ToString)
> strSurname = objDataSet.Tables("tblStudent").Rows(j -
> 1).Item("SName")
> strFirstName = objDataSet.Tables("tblStudent").Rows(j -
> 1).Item("FName")
> lstStudents51.Items.Add(objRow.Item(strSurname + ", " +
> strFirstName))
> Next
>
> lstStudents51.SelectedIndex = 0
>
> End Sub
>
> The error is : "Column 'Clancy, Martina' does not belong to the table
> tblStudent"
> The column the error refers to is the first column in tblStudent. My
> database is called tblStudent and its not a spelling mistake or
> anything.
> Can you help with this little error please?
>
>
>
> Cerebrus wrote:
> > Laura,
>
> > I agree with "The_Fruitman" on this... Your design appears to be so
> > deeply flawed (it violates the very tenets of programming) that it
> > seems that your actual problem at hand is insignificant in comparison.
> > I seriously hope we have misunderstood you and you are not using a
> > separate form for each class... sounds like there are atleast 51 of
> > these classes.
>
> > On Jan 15, 8:10 pm, The_Fruitman <[email protected]> wrote:
> > > Please tell me you aren't building a separate form for each class.
> > > This is a bad design and should be avoided at all costs because of
> > > several issues (these are the ones that quickly come to mind):
> > > 1. What happens when a new class is added? Will you have to build
> > > another form?
> > > 2. What happens if a class has been removed? Do you need to remove or
> > > hide the form?
> > > 3. Having each class as a separate form means that you have duplicate
> > > code all over the place, this is also something that should be
> > > avoided. For one reason, if you have to make modifications to the
> > > code, you have to change it in multiple areas.
>
> > > If you must display the listing of students for a selected class in
> > > another form there are other ways to do it. For example you may pass
> > > the selected class id to the attendance form. This would allow you to
> > > use the same form for all your classes (a much better design). On the
> > > form load of the attendance form you would grab the passed in class id
> > > and use it as a parameter in your sql statement to populate your
> > > dataset. From there you can then do your adding of information from
> > > the dataset to the listbox or whatever other controls you wish to
> > > populate witih the information.
>
> > > On Jan 14, 9:01 am, Laura <[email protected]> wrote:
>
> > > > Hi,
>
> > > > I have a database with a Student table and a Class table. A number of
> > > > students are members of a particular class.
>
> > > > On my windows form I need to display student names in a listbox. I
> > > > then have a different form for each class. So for example (as per code
> > > > below) this form is for Class51. The code I have so far is reading in
> > > > all student names into the listbox. I need it to read in the names of
> > > > those students in Class51.
>
> > > > Each class has a classID. I know in SQL I would simply say SELECT *
> > > > FROM STUDENT WHERE CLASSID = 8, but what do I need to add to my code
> > > > here.
>
> > > > Any help would be really appreciated.
>
> > > > Private Sub frmAttendace51_Load(ByVal sender As System.Object, ByVal e
> > > > As System.EventArgs) Handles MyBase.Load
>
> > > > 'clear data set of any existing data
> > > > objDataSet.Clear()
> > > > 'fill schema
> > > > objStudentDA.FillSchema(objDataSet, SchemaType.Source,
> > > > "tblStudent")
> > > > 'fill data set with info from data adapter
> > > > objStudentDA.Fill(objDataSet, "tblStudent")
>
> > > > 'fill the data set with info from tblClass
> > > > objClassDA.FillSchema(objDataSet, SchemaType.Source,
> > > > "tblClass")
> > > > objClassDA.Fill(objDataSet, "tblClass")
>
> > > > 'fill the data set with info from tblClass
> > > > objAttendanceDA.FillSchema(objDataSet, SchemaType.Source,
> > > > "tblAttendance")
> > > > objAttendanceDA.Fill(objDataSet, "tblAttendance")
>
> > > > 'setup the relationship
> > > > objDataSet.Relations.Clear()
> > > > objDataSet.Relations.Add("Class2Student", _
> > > > objDataSet.Tables("tblClass").Columns
> > > > ("ClassID"), _
> > > > objDataSet.Tables
> > > > ("tblStudent").Columns("ClassID"))
> > > > objDataSet.Relations.Add("Student2Attendance", _
> > > > objDataSet.Tables
> > > > ("tblStudent").Columns("StudentID"), _
> > > > objDataSet.Tables
> > > > ("tblAttendance").Columns("StudentID"))
>
> > > > lstStudents51.Items.Clear()
>
> > > > Dim i As Integer
> > > > Dim strSurname As String
> > > > Dim strFirstName As String
> > > > For i = 1 To objDataSet.Tables("tblStudent").Rows.Count
> > > > strSurname = objDataSet.Tables("tblStudent").Rows(i -
> > > > 1).Item("SName")
> > > > strFirstName = objDataSet.Tables("tblStudent").Rows(i -
> > > > 1).Item("FName")
> > > > lstStudents51.Items.Add(strSurname + ", " + strFirstName)
> > > > Next
>
> > > > lstStudents51.SelectedIndex = 0- Hide quoted text -
>
> > > - Show quoted text -- Hide quoted text -
>
> - Show quoted text -
