Read PDF doc to axAcroPDF c#

Question

I need to read from ms sql file to adobe PDF reader

Error is line 8

 
Error CS0029 Cannot implicitly convert type 'System.IO.MemoryStream' to 'string'

 

Some help?

try
                {
                    if (documentsDataGridView.SelectedRows[0].Cells["pdf_file"].Value != null)
                    {
                        byte[] ap = (byte[])documentsDataGridView.SelectedRows[0].Cells["pdf_file"].Value;
                        MemoryStream ms = new MemoryStream(ap);

                        axAcroPDF1.src = ms;



                    }
                    else {
                        axAcroPDF1.src = null;
                    }
                }
                catch
                {
                    axAcroPDF1.src = null;
                }