print problem in win form

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C#

I have many forms with data grid view and I have print button in my forms that print from data grid view I download one class print.DVG from internet and write

private void Print_Click(object sender, EventArgs e)//print
{
   PrintDGV.Print_DataGridView(dataGridViewX1);
}

and I build one form printoptions but this error appereance
object reference not set to an instance of an object