在vb.net的组合框中检索记录

Question

I have a stored procedure and i want to display the record to a combobox . But it says that

There is no row at position 0 at this line.

cboSchoolYear.Text = (dt.Rows(0)("Schoolyear")) 

stored procedure code:

ALTER PROCEDURE [dbo].[uspLatestDateEnrolled]
    -- Add the parameters for the stored procedure here

@studID INT


AS
BEGIN
    -- SET NOCOUNT ON added to prevent extra result sets from
    -- interfering with SELECT statements.
    SET NOCOUNT ON;

    -- Insert statements for procedure here
    SELECT TOP 1 DateEnrolled as LatestDate,
    SchoolYear,Levels,Section,StudentID
    FROM StudentHistory
    WHERE studentID = @studID
    ORDER BY DateEnrolled DESC
END

Vb.net code

   cn.Open()
        Using cmd As New SqlClient.SqlCommand("uspLatestDateEnrolled", cn)
            cmd.CommandType = CommandType.StoredProcedure
            cmd.Parameters.Add(New SqlParameter("@studID", frmView.dgv1.SelectedCells(0).Value))
            cboSchoolYear.Text = (dt.Rows(0)("Schoolyear"))
            cboGradeLevel.Text = (dt.Rows(1)("levels"))
            cboSection.Text = (dt.Rows(2)("Section"))
            dtpEnrollment.Text = (dt.Rows(3)("dateEnrolled"))
        End Using
        cn.Close()

Answer 1

While doing some research, This code solve my problem. Thank you to Codexer, for giving me some tips.

  Try
        cn.Open()
        cmd = New SqlCommand("uspLatestDateEnrolled", cn)
        cmd.Parameters.AddWithValue("@studID", frmView.dgv1.SelectedCells(0).Value)
        cmd.CommandType = CommandType.StoredProcedure
        da.SelectCommand = cmd
        da.Fill(dt)
        cboSchoolYear.Text = dt.Rows(0).Item("SchoolYear")
        cboGradeLevel.Text = dt.Rows(0).Item("levels")
        cboSection.Text = dt.Rows(0).Item("Section")
        dtpEnrollment.Text = dt.Rows(0).Item("DateEnrolled")

    Catch x As Exception
        MessageBox.Show(x.GetBaseException().ToString(), "Error", MessageBoxButtons.OK, MessageBoxIcon.[Error])
    Finally
        cmd.Dispose()
        cn.Close()
    End Try

Answer 2

You've got a couple things that are wrong here (or a couple things wrong and a couple things missing from the post)

1. You never declare DT
2. You are jumping rows, if you returned more then one result (which you don't because of the top 1 in your sql you would be getting information from different records)
3. You don't check to see if you return anything from the database

Your vb.net code should look something like this (this code isn't perfect, but its should get you moving in the correct direction)

    cn.Open()
    Using cmd As New SqlClient.SqlCommand("uspLatestDateEnrolled", cn)
        cmd.CommandType = CommandType.StoredProcedure
        cmd.Parameters.Add(New SqlParameter("@studID", frmView.dgv1.SelectedCells(0).Value))

    Dim SQLDataReader as SQLDataReader = cmd.executeReader()

    if sqldatareader.hasrows = true then 
    while sqldatareader.read

        if sqldatareader("Schoolyear") isnot dbnull.value then 
                cboSchoolYear.Text = sqldatareader("Schoolyear")
        else
                cboSchoolYear.Text = "Null"
        end if
        if sqldatareader("levels") isnot dbnull.value then 
                cboGradeLevel.Text = sqldatareader("levels")
        else
                cboGradeLevel.Text = "Null"
        end if
        if sqldatareader("Section") isnot dbnull.value then 
                cboSection.Text = sqldatareader("Section")
        else
                cboSection.Text = "Null"
        end if
        if sqldatareader("dateEnrolled") isnot dbnull.value then 
                cboSection.Text = sqldatareader("dateEnrolled")
        else
                cboSection.Text = "Null"
        end if

    loop
    else
       'No Results
    end if 

    End Using
    cn.Close()