Question

I have a List<ColumnList> ColumnListLists which has a binding source (bsLists) attached to it. ColumnList has a List<Column> inside of it. I have a binding source attached to the current of bsLists pointing at that inner list.

Confused yet? here is some code that may help.

public class ColumnList
{
     ...
     public string Name { get; set;}
     public List<Column> ListOfColumns { get; set;}
}

public class Column
{
    ...
    public string HeaderName { get; set; }
}

public class CustContractsSetup
{
    public CustContractsSetup()
    {
        InitializeComponent();
        bsLists = new BindingSource(Properties.Settings.Default.ColumnListLists, null);
        cmbListName.DataSource = bsLists;
        cmbListName.DisplayMember = "Name";
        bsColumns = new BindingSource(bsLists, "ListOfColumns");
        lbCurrent.DataSource = bsColumns;
        lbCurrent.DisplayMember = "HeaderName";
    }
    BindingSource bsLists;
    BindingSource bsColumns;
    ListBox lbCurrent;
}

Now what I want to do is change the order of two Column‘s.

private void btnUp_Click(object sender, EventArgs e)
{
    if (lbCurrent.SelectedIndex <= 0 || lbCurrent.SelectedIndex > bsColumns.Count)
        return;
    System.Diagnostics.Debug.Print("before:");
    Debug.Print(((ColumnList)bsLists.Current).ListOfColumns[lbCurrent.SelectedIndex - 2].HeaderName);
    Debug.Print(((ColumnList)bsLists.Current).ListOfColumns[lbCurrent.SelectedIndex - 1].HeaderName);
    Debug.Print(((ColumnList)bsLists.Current).ListOfColumns[lbCurrent.SelectedIndex].HeaderName);
    Debug.Print(((ColumnList)bsLists.Current).ListOfColumns[lbCurrent.SelectedIndex + 1].HeaderName);
    Debug.Print(((ColumnList)bsLists.Current).ListOfColumns[lbCurrent.SelectedIndex + 2].HeaderName);
    ((ColumnList)bsLists.Current).ListOfColumns.Reverse(lbCurrent.SelectedIndex - 1, 1);
    Debug.Print("after:");
    Debug.Print(((ColumnList)bsLists.Current).ListOfColumns[lbCurrent.SelectedIndex - 2].HeaderName);
    Debug.Print(((ColumnList)bsLists.Current).ListOfColumns[lbCurrent.SelectedIndex - 1].HeaderName);
    Debug.Print(((ColumnList)bsLists.Current).ListOfColumns[lbCurrent.SelectedIndex].HeaderName);
    Debug.Print(((ColumnList)bsLists.Current).ListOfColumns[lbCurrent.SelectedIndex + 1].HeaderName);
    Debug.Print(((ColumnList)bsLists.Current).ListOfColumns[lbCurrent.SelectedIndex + 2].HeaderName);
    bsLists.ResetCurrentItem();
}

And this is the output I get

before:
Conversion Level
Conversion Programmer
Edge Required
Education Required
Target Month
after:
Conversion Level
Conversion Programmer
Edge Required
Education Required
Target Month

If things worked as they should Edge Required should have swapped with Conversion Programmer. but as you can see the before and after list are exactly the same.

What kind of mistake am I making that is keeping my list from having the order changed?

Answer 1

I think your basic problem is the size of the Reverse range, try:

 .Reverse(lbCurrent.SelectedIndex - 1, 2);