Save row colour after closing form - vb.net

Question

I got this for saving all data when closing the form.
Public Class Form1
Dim table As New DataTable("Table")
ReadOnly p As String = Path.Combine("C:\test.xml")
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
DataGridView1.SelectionMode = DataGridViewSelectionMode.FullRowSelect
If Not File.Exists(p) Then
table.Columns.Add("Company", Type.GetType("System.String"))
table.Columns.Add("Date", Type.GetType("System.DateTime"))
table.Columns.Add("Code", Type.GetType("System.String"))
table.Columns.Add("Position", Type.GetType("System.String"))
table.Columns.Add("Note", Type.GetType("System.String"))
table.Columns.Add("Solved", Type.GetType("System.DateTime"))
Else
table.ReadXml(p)
End If
DataGridView1.DataSource = table
End Sub
I was using this for mark solved row:
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
DataGridView1.CurrentRow.DefaultCellStyle.BackColor = Color.PaleGreen
DataGridView1.CurrentRow.Cells("Solved").Value = DateTime.Now
DataGridView1.DataSource = table
DataGridView1.ClearSelection()
End Sub
And this for "repair solved row" button:
Private Sub Button4_Click(sender As Object, e As EventArgs) Handles Button4.Click
DataGridView1.CurrentRow.DefaultCellStyle.BackColor = Color.White
DataGridView1.CurrentRow.Cells("Solved").Value = ""
DataGridView1.DataSource = table
DataGridView1.ClearSelection()
End Sub
The problem is, that my saving doesn't save this coloured row, it's white when I open the form again.
Any idea? I'm really new to this.
Thanks.

Answer 1

The following code should color the rows as described in my comments.
Private Sub ColorRows()
For Each row As DataGridViewRow In DataGridView1.Rows
If (Not row.IsNewRow) And (row.Cells("Solved").Value IsNot DBNull.Value) Then
row.DefaultCellStyle.BackColor = Color.PaleGreen
End If
Next
End Sub
You could call this code in the forms Load event right after the data has been loaded into the grid. Something like…
….
DataGridView1.DataSource = table
ColorRows()
Edit...
After some testing, it appears that when the code is setting the "Solved" value to an empty string, in the Button4_Click event with...
DataGridView1.CurrentRow.Cells("Solved").Value = ""
This is setting a default min Date value as you noted in the xml file.
Change this line of code to...
DataGridView1.CurrentRow.Cells("Solved").Value = DBNull.Value
It should work as expected then.
Below is the complete code I used to test this.
Dim table As New DataTable("Table")
ReadOnly p As String = Path.Combine("D:\Test\XML\_test_100.xml")
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
DataGridView1.SelectionMode = DataGridViewSelectionMode.FullRowSelect
If Not File.Exists(p) Then
table.Columns.Add("Company", Type.GetType("System.String"))
table.Columns.Add("Date", Type.GetType("System.DateTime"))
table.Columns.Add("Code", Type.GetType("System.String"))
table.Columns.Add("Position", Type.GetType("System.String"))
table.Columns.Add("Note", Type.GetType("System.String"))
table.Columns.Add("Solved", Type.GetType("System.DateTime"))
Else
table.ReadXml(p)
End If
DataGridView1.DataSource = table
ColorRows()
End Sub
Private Sub ColorRows()
For Each row As DataGridViewRow In DataGridView1.Rows
If (Not row.IsNewRow) And (row.Cells("Solved").Value IsNot DBNull.Value) Then
row.DefaultCellStyle.BackColor = Color.PaleGreen
End If
Next
End Sub
Private Sub btnWriteToXML_Click(sender As Object, e As EventArgs) Handles btnWriteToXML.Click
table.WriteXml(p, XmlWriteMode.WriteSchema)
End Sub
Private Sub btnSolved_Click(sender As Object, e As EventArgs) Handles btnSolved.Click
DataGridView1.CurrentRow.DefaultCellStyle.BackColor = Color.PaleGreen
DataGridView1.CurrentRow.Cells("Solved").Value = DateTime.Now
'DataGridView1.DataSource = table
DataGridView1.ClearSelection()
End Sub
Private Sub btnRepairSolved_Click(sender As Object, e As EventArgs) Handles btnRepairedSolved.Click
DataGridView1.CurrentRow.DefaultCellStyle.BackColor = Color.White
DataGridView1.CurrentRow.Cells("Solved").Value = DBNull.Value
'DataGridView1.DataSource = table
DataGridView1.ClearSelection()
End Sub