Little help with DataGridView please

Little help with DataGridView please

• Daniel2005

  MadAboucC, i tried your code which works but i lose my column styles i created in VS2005 properties window/columns collection when i re-populate my dataGridView.

  Any ideas

  
  

• Horst Klein

  By the way, Did you try:

  dataGridView.Rows.Clear();
  arrayList.Clear();

  This will clear the rows keeping the data source as the arraylist!

  Hope it helps!

  
  
  

• ClydeCoulter

  Ken Tucker wrote:

  I would recommend you use the BindingList instead of a Arraylist because it is set up for databinding. If you want the datagridview to be sortable check out this article on adding Sorting to BindingList

  I tried using a BindingList and it works great. thank you.

  
  

• ZopoStyle

  It works but it puts my columns in wrong order.Any ideas
  

• Barron Gillon

  I've been trying this for a while now, and here's what i got:

  It seems that when you detach the DataSource property, all columns and column styles are cleared, so to repopulate, you will have to recreate the DataGridView control's styles all over again. For example, I created a class Student and stored multiple instances in an array list, added a DataGridView control and two buttons. The first will simply clear the DGV and the second attempts to repopulate it without loosing the format and styles. The student class has a name, an id, a guid, a datereg and an acummAverage (sample properties). These properties map to five columns. So i designed the DGV in design view like you did, added five columns with header names and properties. The problem was the order of the population when trying to re-populate the columns. I went to the Form1.Designer.cs file (expand your form's class file in solution explorer and you'll see it) and copied the lines to recreate the DataGridView columns collection from there and pasted it into a method, then, at repopulation i called that method to recreate the columns collection of the DGV. This and only this worked! Hope that this example helps you in your case and can be easily transfered (at least the methodology it self). I included the full code for you to see:

  In the main form of you application, switch to code view and add the following lines to the Form1 class:

  private ArrayList dsArr = new ArrayList(20);
  public Form1() {

  for (int i = 0; i < 20; i++) {dsArr.Add(new Studnet());}
  InitializeComponent();
  dataGridView1.DataSource = dsArr;

  }

• bobslayer

  gafferuk wrote:

  MadAboutC# wrote: By the way, Did you try: dataGridView.Rows.Clear(); arrayList.Clear(); This will clear the rows keeping the data source as the arraylist! Hope it helps! I tried it and i received error: Rows collection cannot be programmatically cleared when the DataGridView control is data-bound to anything else than an IBindingList that supports change notification and allows deletion.

  I encounter the same error. Any suggestions, please

  
  

• DmitryMS

  Try this, when assigning null to the DataSource, make a backup of your styles and then when repopulating use the backup to reasign the styles. Another method is to create a method that will set the styles for a datagrid view and maybe another to store them.

  An example of the first method would be:

  DataGridViewHeaderBorderStyle dgvhbs = dgv.ColumnHeadersBorderStyle;
  DataGridViewCellStyle dgvcs = dgv.ColumnHeadersDefaultCellStyle;
  int dgvhh = dgv.ColumnHeadersHeight;
  DataGridViewColumnHeadersHeightSizeMode dgvchhm = dgv.ColumnHeadersHeightSizeMode;
  DataGridViewColumn[] cols = new DataGridViewColumn[dgv.Columns.Count];
  dgv.Columns.CopyTo(cols, 0);
  ---------------------------------------------
  dgv.DataSource = null;
  //.......
  //Your code

• michaelleewebb

  MadAboutC# wrote:

  By the way, Did you try: dataGridView.Rows.Clear(); arrayList.Clear(); This will clear the rows keeping the data source as the arraylist! Hope it helps!

  I tried it and i received error: Rows collection cannot be programmatically cleared when the DataGridView control is data-bound to anything else than an IBindingList that supports change notification and allows deletion.

  
  

• George Shear

  I would recommend you use the BindingList instead of a Arraylist because it is set up for databinding. If you want the datagridview to be sortable check out this article on adding Sorting to BindingList
  
  

• KitGreen

  What's the error that appeared

  Try:

  dataGridView.DataSource = null;
  arrayList.Clear();
  //You might not need this so add it only if the first two lines alone won't work
  dataGridView.Refresh();

  Hope This helps!

  
  
  

• Michael Weingartner

  O.K. I solved it:

  Code Snippet

  BindingSource.DataSource = null;

  DataSet.Clear();

  GridView.DataSource = null;

  GridView.Rows.Clear();

  GridView.Refresh();

  
  

• GetCode

  Eureka!

  I fought with a similar problem for two days. I needed to clear a DataGridView then repopulate it later. All attempts to nullify the data source, or fiddle with the DataTable, or repopulate it using a SELECT statement that returned blank columns... all produced undesirable results. I almost wrote my own initializer like one poster here suggested, but refused to believe I had to go through that much trouble. The answer was pleasingly simple.

  Here's what worked:

  foreach (DataGridViewRow row in myDataGridView.Rows)

  {

  myDataGridView.Rows.Remove(row);

  }

  
  
• Little help with DataGridView please