Following example shows how to change font of the textbox at runtime in vb.net
Example
Private Sub Button1_Click(ByVal sender As System.Object, _ ByVal e As System.EventArgs) Handles Button1.Click Dim objFont As System.Drawing.Font objFont = New System.Drawing.Font("Arial", 12, FontStyle.Bold Or FontStyle.Italic) TextBox1.Font = objFont End Sub
you can also use the FontDialog class for changing font, see this:
Private Sub Button1_Click(ByVal sender As System.Object, _ ByVal e As System.EventArgs) Handles Button1.Click Dim objFontDlg As New FontDialog If objFontDlg.ShowDialog = Windows.Forms.DialogResult.OK Then TextBox1.Font = objFontDlg.Font End If End Sub