VB.NET中的索引超出范围异常

Question

当我运行以下代码时，在ColourAddition（selectedstyle，styleselection.getIndex）=“ Y”行之后，每次都出现错误，并且如果在没有上述行的情况下运行该代码，则该程序成功了。请帮我弄清楚

Public Class Form1
    Dim dbcon As New OleDb.OleDbConnection
    Dim DR As OleDb.OleDbDataReader
    Dim dr1 As OleDb.OleDbDataReader
    Dim com As New OleDb.OleDbCommand
    Dim com1 As New OleDb.OleDbCommand
    Dim ChkdItm As Integer
    Dim NoOfStyles As Integer
    Dim NoOfColours As Integer
    Dim SelectedStyle As Integer
    Dim temp As Integer

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        dbcon.ConnectionString = "Provider= Microsoft.Ace.OLEDB.12.0; Data Source= CheckedListBox.accdb"
        dbcon.Open()
        com.CommandText = "Select * from ColourTable"
        com1.CommandText = "Select * from StyleTable"
        com1.Connection = dbcon
        com.Connection = dbcon
        DR = com.ExecuteReader
        dr1 = com1.ExecuteReader
        While dr1.Read
            NoOfStyles += 1
        End While
        While DR.Read
            ColoursClb.Items.Add(DR.GetString(1))
            NoOfColours += 1
        End While
        SelectedStyle = StyleSelection.getIndex
    End Sub
    Public colourAddition(NoOfStyles, NoOfColours) As String

    Private Sub AddColourBtn_Click(sender As Object, e As EventArgs) Handles AddColourBtn.Click
        If ColoursClb.CheckedItems.Count > 0 Then
            For Each ChkdItm In ColoursClb.CheckedIndices
                colourAddition(SelectedStyle, StyleSelection.getIndex) = "Y"
            Next
        End If
    End Sub

    Private Sub Form1_Closed(sender As Object, e As EventArgs) Handles Me.Closed
        StyleSelection.Show()
    End Sub
End Class

该错误显示在写入“下一步”的行上