C# Datagrid is not resizing with WinForm

Question

I have bound some data to a DataGrid in a WinForm. Regardless of what I did on changing the size of the columns (like AutoSizeMode and DataGridViewAutoSizeColumnMode), I can't get my DataGrid to fill my WinForm, and when I resize the WinForm, the Datagrid size is fixed and is not resizing with the WinForm. Either I get a scrollbar if is the dataGrid is bigger than the form, or I have a huge space left after the last column.

I have got a result like in the picture below. Can anyone help to make the datagrid fit the form, and have it resize with the Form? Thank you.

This is not my DataGrid, just a picture from the internet, but it has the same result as mine.

Here is the code

enter link description here

PS: I haven't found a 100% solution yet, but a workaround, the problem was that the DataGrid source was a DataTable which had a DataTableStyle, and that one resize all the columns somehow (still couldn't figure out were exactly).So my workaround was that I added an Auto Align button in the menu, which reset the columns width by calculating the DataGridView width, and just devid it by the number of the columns in the DataTable and then it resizes each column.width in the DataTablestyle and voilà

Answer 1

There is property on DataGridView called AutoSizeColumnMode make sure you set it to Fill if you want to reach desired effect (see the pic bellow). And with that also note that you need to set the AutoSizeMode to Fill for at least one Column.

EDIT:

Ok i'll do an example for you. Let's say you've got WinForm application with one empty Form named Form1. Just copy paste the code bellow into your form and tell me if it works as you want:

        DataGridView dataGridView1;

        public Form1()
        {
            InitializeComponent();
            dataGridView1 = new System.Windows.Forms.DataGridView();
            dataGridView1.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.Fill;
            dataGridView1.Dock = DockStyle.Fill;
            // we will create two columns that will resize based on content within cells
            for (var i = 0; i < 2; i++)
            {
                var column = new DataGridViewTextBoxColumn()
                {
                    HeaderText = $"Column{i} - AllCells",
                    AutoSizeMode = DataGridViewAutoSizeColumnMode.AllCells
                };
                dataGridView1.Columns.Add(column);
            }
            // And one column that fill fill the rest of the grid 
            var fillColumn = new DataGridViewTextBoxColumn()
            {
                HeaderText = "FillColumn",
                AutoSizeMode = DataGridViewAutoSizeColumnMode.Fill
            };
            dataGridView1.Columns.Add(fillColumn);
            // so we've got grid with 3 columns let's fill some random data
            dataGridView1.Rows.Add("test", "test", "test test test");
            dataGridView1.Rows.Add("test", "test", "test test test");
            dataGridView1.Rows.Add("test", "test", "test test test");
            dataGridView1.Rows.Add("test", "test", "test test test");
            Controls.Add(dataGridView1);
        }

Answer 2

The Anchor property will do the job. Just select all directions (Top, Bottom, Left, Right). You can do it by the designer or programmatically.

this.dataGridView1.Anchor = 
  ((System.Windows.Forms.AnchorStyles) 
  ((((System.Windows.Forms.AnchorStyles.Top 
  | System.Windows.Forms.AnchorStyles.Bottom) 
  | System.Windows.Forms.AnchorStyles.Left) 
  | System.Windows.Forms.AnchorStyles.Right)));

Answer 3

If you want the dataGridView to fill the Form, then there is a property in DataGridView named Dock. Set this property to Fill and the dataGridView will fill the Form completely, even when resizing, it'll be responsive with resizing. This will work for you if you want to fill the form.

But if you have another components in the form, then you have to use Anchor property. Since the dataGridView will be re-sizable with the Form without filling the form completely.