public interface IPersistControl
{
    void LoadControlSettings(PersistControlSettings settings);
    void SaveControlSettings(PersistControlSettings settings);
}

public class PersistControlSettings : IDisposable
{
    public PersistControlSettings(string name) { /* ... */  }

    public PersistControlSettings(string name, PersistControlSettings parent) { /* ... */ }

    public void Dispose() { /* ... */ }

    public PersistControlSettings Child(string name)
    {
        if (name == string.Empty)
        {
            return this;
        }

        return new PersistControlSettings(name, this);
    }

    public object GetValue(string name, object defaultValue) { /* ... */ }

    public void LoadChildStates(Control.ControlCollection children)
    {
        foreach (Control control in children)
        {
            LoadControlState(control);
        }
    }

    private void LoadControlState(Control c)
    {
        IPersistControl pc = c as IPersistControl;

        if (pc != null)
        {
            pc.LoadControlSettings(Child(c.Name));
            return;
        }

        CheckBox cb = c as CheckBox;

        if (cb != null)
        {
            cb.Checked = Convert.ToBoolean(GetValue(String.Format("{0}.Checked", cb.Name), cb.Checked));
            return;
        }

        DataGrid dg = c as DataGrid;

        if (dg != null)
        {
            PersistControlSettings settings = Child(dg.Name);

            foreach (DataGridTableStyle ts in dg.TableStyles)
            {
                DataGridColumnStyle[] columns = new DataGridColumnStyle[ ts.GridColumnStyles.Count ];

                for (int index = 0; index < ts.GridColumnStyles.Count; index++)
                {
                    DataGridColumnStyle cs = ts.GridColumnStyles[ index ];
                    PersistControlSettings child = settings.Child(cs.MappingName);

                    if (cs is Forms.IColumnStyle)
                    {
                        ((Forms.IColumnStyle)cs).AutoFitWidth = Convert.ToBoolean(child.GetValue("AutoFitWidth", ((Forms.IColumnStyle)cs).AutoFitWidth));
                    }

                    cs.Width = Convert.ToInt32(child.GetValue("Width", cs.Width));

                    int i = Convert.ToInt32(child.GetValue("Index", index));

                    if (i < columns.Length && columns[ i ] == null)
                    {
                        columns[ i ] = cs;
                    }
                    else if (null == columns[ index ])
                    {
                        columns[ index ] = cs;
                    }
                }

                ts.GridColumnStyles.Clear();
                ts.GridColumnStyles.AddRange(columns);
            }

            return;
        }

        DateTimePicker dt = c as DateTimePicker;

        if (dt != null)
        {
            bool isChecked = Convert.ToBoolean(GetValue(String.Format("{0}.Checked", dt.Name), dt.Checked));

            if (isChecked)
            {
                dt.Value = Convert.ToDateTime(GetValue(String.Format("{0}.Value", dt.Name), dt.Value));
                dt.Checked = isChecked;
            }

            return;
        }

        Splitter sp = c as Splitter;

        if (sp != null)
        {
            sp.SplitPosition = Convert.ToInt32(GetValue(String.Format("{0}.SplitPosition", sp.Name), sp.SplitPosition));
            return;
        }

        TextBox tb = c as TextBox;

        if (tb != null && tb.Text == string.Empty && tb.PasswordChar == 0 && !tb.ReadOnly)
        {
            tb.Text = Convert.ToString(GetValue(String.Format("{0}.Text", tb.Name), tb.Text));
            return;
        }

        if (c is ScrollableControl || c is TabControl || c is ToolBar || c is GroupBox)
        {
            Child(c.Name).LoadChildStates(c.Controls);
            return;
        }
    }

    public void SaveChildStates(Control.ControlCollection children)
    {
        foreach (Control control in children)
        {
            SaveControlState(control);
        }
    }

    private void SaveControlState(Control control)
    {
        IPersistControl pc = control as IPersistControl;

        if (pc != null)
        {
            pc.SaveControlSettings(Child(control.Name));
            return;
        }

        CheckBox cb = control as CheckBox;

        if (cb != null)
        {
            SetValue(String.Format("{0}.Checked", cb.Name), cb.Checked);
            return;
        }

        DataGrid dg = control as DataGrid;

        if (dg != null)
        {
            PersistControlSettings settings = Child(dg.Name);

            foreach (DataGridTableStyle ts in dg.TableStyles)
            {
                for (int index = 0; index < ts.GridColumnStyles.Count; index++)
                {
                    DataGridColumnStyle cs = ts.GridColumnStyles[ index ];
                    PersistControlSettings child = settings.Child(cs.MappingName);

                    if (cs is Forms.IColumnStyle)
                    {
                        child.SetValue("AutoFitWidth", ((Forms.IColumnStyle)cs).AutoFitWidth);
                    }

                    child.SetValue("Index", index);
                    child.SetValue("Width", cs.Width);
                }
            }

            return;
        }

        DateTimePicker dt = control as DateTimePicker;

        if (dt != null)
        {
            SetValue(String.Format("{0}.Checked", dt.Name), dt.Checked);
            SetValue(String.Format("{0}.Value", dt.Name), dt.Value);
            return;
        }

        Splitter sp = control as Splitter;
        if (sp != null)
        {
            SetValue(String.Format("{0}.SplitPosition", sp.Name), sp.SplitPosition);
            return;
        }

        TextBox tb = control as TextBox;

        if (tb != null && tb.PasswordChar == 0)
        {
            SetValue(String.Format("{0}.Text", tb.Name), tb.Text);
            return;
        }

        if (control is ScrollableControl || control is TabControl || control is ToolBar || control is GroupBox)
        {
            Child(control.Name).SaveChildStates(control.Controls);
            return;
        }
    }

    public void SetValue(string name, object value) { /* ... */ }
}