the DataGridViewColumn.FillWeight property represents the width of the column when it is in fill mode relative to the widths of other fill-mode columns in the control. You use it to create equal width columns.
The following example create three columns with equal width in the DataGridView:
dataGridView1.AutoSizeColumnsMode =
DataGridViewAutoSizeColumnsMode.Fill;
DataGridViewTextBoxColumn subTitleColumn =
new DataGridViewTextBoxColumn();
subTitleColumn.HeaderText = "Subtitle";
subTitleColumn.MinimumWidth = 100;
subTitleColumn.FillWeight = 100;
DataGridViewTextBoxColumn summaryColumn =
new DataGridViewTextBoxColumn();
summaryColumn.HeaderText = "Summary";
summaryColumn.MinimumWidth = 100;
summaryColumn.FillWeight = 100;
DataGridViewTextBoxColumn contentColumn =
new DataGridViewTextBoxColumn();
contentColumn.HeaderText = "Content";
contentColumn.MinimumWidth = 100;
contentColumn.FillWeight = 100;