Saving user's DataGridViewColumn widths for multiple forms/controls - vb.net

Question

Typically, when designing a DataGridView, I try to size the columns so that nothing will need to be resized by the user. This practice works most of the time, but I recently had a user change her Windows settings so that text would display larger than usual.
That single act broke all of the tedious sizing that I worked so hard on. I have looked into saving column width per user and allowing them to be saved to the registry. The issue I run into is having to create a field in the application settings for each and every value that I want to save to the registry.
When saving settings for a single form, that is not a problem, and I do use the application settings for this purpose to save the main window size/location so that users can determine the optimal view of the application.
My question is:
Is there a way to save an array to the registry, or perhaps otherwise save dynamic values into the registry, without adding these values to the application settings in advance? Ideally, I will just have a "ColumnWidths" application setting or something along those lines, and dynamically add column name/width for any column that is resized by the user.
I have the following code, which is fine if I add a new setting for each individual form that I want to save sizing for, but I'm hoping to achieve this with a single setting, that will save column sizing for multiple DataGridView/Forms.
Private Sub SaveColumnSettings()
If My.Settings.CustomColumnWidths Is Nothing Then
My.Settings.CustomColumnWidths = New StringCollection
End If
For Each dc As DataGridViewColumn In grdBackOrderedItems.Columns
My.Settings.CustomColumnWidths.Add(dc.Width.ToString())
Next
End Sub
Private Sub LoadColumnSettings()
For i As Integer = 0 To My.Settings.CustomColumnWidths.Count - 1
grdBackOrderedItems.Columns(i).Width = CInt(My.Settings.CustomColumnWidths(i))
Next
End Sub

Answer 1

Settings allows for a Collection type, however it is a string collection (initial post seemed not to know this).
The current edit is dicey since it assumes one collection will fit all DGVs on all forms (that is, the same number of columns for all of them) and you are only adding to the Collection every time you save - making it larger. Since you want to save the users optimal view you should have one collection per DGV since they might well make col4 on DGVFoo wider than elsewhere.
Rather than adding a collection Setting for each DGV (ie "DGVFooColumns", "DGVBarColumns" etc), which requires each one be hard coded to map to the correct entry, I would use a custom class and serialize it.
Most everything regarding them can be internalized to the class. This is not a finished class, but a rough out of making one class service any and all DGVs (it should be very close):
' for the collection
Imports System.Collections.ObjectModel
Imports System.Runtime.Serialization.Formatters.Binary
<Serializable>
Public Class GridLayouts
<Serializable>
Friend Class GridLayout
Public Property GridName As String
Public Widths As New List(Of Integer)
' Some Serializers will require a simple ctor
Public Sub New()
Widths = New List(Of Integer)
End Sub
Public Sub SaveLayout(name As String, dgv As DataGridView)
' something the code uses to map them
' other than "DataGridView1" of which there may be several
GridName = name
' ToDo: loop thru DGV save widths to Widths
End Sub
End Class
Private mCol As Collection(Of GridLayout)
Private myFile As String
Public Sub New(filename As String)
myFile = filename
mCol = New Collection(Of GridLayout)
End Sub
Private Function IndexOf(grdName As String) As Integer
For n As Integer = 0 To mCol.Count - 1
If grdName = mCol(n).GridName Then
Return n
End If
Next
Return -1 ' not found
' alternatively find by name:
'Dim item = mCol.FirstOrDefault(Function(i) i.GridName = grdName)
'Return item
End Function
Public Sub StoreLayout(name As String, dgv As DataGridView)
Dim ndx As Integer = IndexOf(name)
If ndx <> -1 Then
mCol.RemoveAt(ndx) ' throw away old one
End If
Dim grd As New GridLayout
grd.SaveLayout(name, dgv)
mCol.Add(grd)
End Sub
Public Sub RestoreLayout(name As String, dgv As DataGridView)
Dim ndx As Integer = IndexOf(name)
If ndx = -1 Then
Exit Sub
End If
For n As Integer = 0 To mCol(ndx).Widths.Count - 1
' loop thru grid and set the columns
' maybe check that the col sizes are equal
dgv.Columns(n).Width = mCol(n).Widths(n)
Next n
End Sub
Public Sub Save()
' ToDo: Make a backup (?)
' Add a Try/Catch and convert to function
Dim bf As New BinaryFormatter
Using fs As New FileStream(myFile, FileMode.OpenOrCreate)
bf.Serialize(fs, mCol)
End Using
End Sub
Public Sub Load()
Dim bf As New BinaryFormatter
Using fs As New FileStream(myFile, FileMode.Open)
mCol = CType(bf.Deserialize(fs), Collection(Of GridLayout))
End Using
End Sub
End Class
Notes:
1) The Example has SaveLayout at the Class-Item level and RestoreLayout at the Collection Level. I would pick one way or the other not split it. This is was for illustrative purposes. I would generally favor the ClassItem Level for both.
2) Rather than the BinaryFormatter, you can use the XML Serializer. I personally loathe it.
3) Note that the collection class saves/loads its own data.
4) System.Collections.ObjectModel is required for Collection(of T) and prevent VB from wanting the use the vile VisualBasic Collection (which stores only Object).
5) Code elsewhere could be optimized so that you only store a layout if they actually change the widths and click something (or have an AutoSaveChanges option).
6) A fair amount is riding on the names being unique so that the layouts can be found.
Usage
Dim SaveFile As String = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData),
CompName,
ProgramName,
filename)
' e.g C:\Users\Ziggy\MyCompany\ThisProd\GridSettngs.bin
' application-wide collection of grid layouts for this user
Private myGrids As New GridLayouts(SaveFile)
...
myGrids.StoreLayout("Customers", datagridView12)
myGrids.RestoreLayout("Orders", datagridView34)