C#

class Form1 : System.Windows.Forms.Form
{

  bool shown = false;

  ...

  private void Form1_Activated(object sender, System.EventArgs e)
  {
    if (!shown)
    {
      shown = true;
      MessageBox.Show("I'm here.");
    }
  }
}

class Form1 : System.Windows.Forms.Form
{
  public Form1()
  {
    InitializeComponent();
  
    this.Activated += new EventHandler(Activated_PerformOnce);
  }

  private void Activated_PerformOnce(object sender, System.EventArgs e)
  {
    this.Activated -= new EventHandler(Activated_PerformOnce);
 
    // Do your on form show stuff
  }
}

// columnIndex must be set to a number.
int columnIndex = 1;
// remove the second column
GridColumnStylesCollection myGridColumns;
myGridColumns = dataGrid1.TableStyles[0].GridColumnStyles;
myGridColumns.RemoveAt( columnIndex );

GridColumnStylesCollection myGridColumns;
myGridColumns = dataGrid.TableStyles[0].GridColumnStyles;
 
foreach(DataGridColumnStyle style in myGridColumns)
{
  // GetColumnWidth takes the header name and returns the width the column should be
  style.Width = GetColumnWidth(style.HeaderName);
}

if(checkBox1.Checked)
{
    MessageBox.Show("Checkbox1 is checked");
}

if (radioButton1.Checked)
{
    MessageBox.Show("radioButton1 is checked");
}