Validate Check box before printing

Question

I have 3 checkboxes that at least one needs to be checked before printing. I have the check boxes linked to the Print button. when i click print a message box states to check one box. when i check the box nothing happens. private void btnPrint_Click(object sender, EventArgs e) { try { if (!checkBox1.Checked && !checkBox2.Checked && !checkBox3.Checked) { MessageBox.Show("Please select one !"); } } catch (Exception ex) { printDocument1.PrintPage += printDocument1_PrintPage; printDocument1.Print(); } } private void printDocument1_PrintPage_1(object sender, PrintPageEventArgs e) { try { e.PageSettings.Landscape = true; Bitmap bm = new Bitmap(this.panel.Width, this.panel.Height); panel.DrawToBitmap(bm, new Rectangle(0, 0, this.panel.Width, this.panel.Height)); e.Graphics.DrawImage(bm, 0, 0, bm.Width, bm.Height); } catch (Exception ex) { string s1 = ex.Message; } } } }

Amit Gupta · Answer

If it need to check the one of three checkboxes then use OR operator instead of AND Edited: private void btnPrint_Click( object sender, EventArgs e) { try { if (checkBox1.Checked || checkBox2.Checked || checkBox3.Checked) { printDocument1.PrintPage += printDocument1_PrintPage; printDocument1.Print(); } else MessageBox.Show( "Please select one !" ); } catch (Exception ex) { } }

Tapan Patel · Answer

I think you need to go through basics of Try Catch block. https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/try-catch so how it works: Anything you think could throw an error ( or something could go wrong with this code), you need to put those code line in try block and if that code throws an error , we use catch block to recieve that error and then you can either log that error or take appropriate action. As those two lines were in catch block, and your code didn't throw any error, it never executed lines in catch block.

Amit Gupta · Answer

That was a part of your working module i.e it invoke your print event and modify your rendering printing page, that you had coded in your exception's body. The catch part will only being invoked when there is any exception.

Tapan Patel · Answer

Ofcourse you need OR conditions and then you need to take out below code from Catch block and put it in try block printDocument1.PrintPage += printDocument1_PrintPage; printDocument1.Print(); try { if (!checkBox1.Checked && !checkBox2.Checked && !checkBox3.Checked) { MessageBox.Show( "Please select one !" ); return ; // Need to select one checkbox } printDocument1.PrintPage += printDocument1_PrintPage; printDocument1.Print(); } catch (Exception ex) { // You don't need this here. //printDocument1.PrintPage += printDocument1_PrintPage; //printDocument1.Print(); }

Amit Gupta · Answer

Apart from that, it was also noticed that print event and your print method name are not matched, I was surprised, how it complies, doesn't you got any compilation error? private void printDocument1_ PrintPage (object sender, PrintPageEventArgs e)

james james · Answer

the OR makes me loop through each of the check boxes but still not printing.

james james · Answer

I got no error from the original code, could you explain for me and other edicational. why did it not compile with the code below added? //printDocument1.PrintPage += printDocument1_PrintPage; //printDocument1.Print(); great work guys

james james · Answer

Thanks for the help guys thats exactly what i was missing.

Validate Check box before printing

Sam Hobbs

Vikas Ahlawat