[Andrew74]

I'm trying to sort this list of movie object I have by year, rating, and quality. I have 3 domain Up Down controls for the variables and check boxes to enable that type of sorting. I bunched it all into one if statement and it's not bring up any results to the data grid. I'm sure I messed up the If statement order or I'm completely doing it wrong.

Any help is much appreciated.
Thanks in advanced.

foreach (MovieData m in Movies)
            {
                if ((m.year.ToString() == domainUpDown1.SelectedItem.ToString() & checkBox1.Checked) &&

                    (m.Rating > double.Parse(domainUpDown2.SelectedItem.ToString()) & checkBox2.Checked) &&

                    (GetQualityIndex(m.Quality) == domainUpDown3.SelectedItem.ToString() & checkBox3.Checked) )
                {
                    n = dataGridView1.Rows.Add();
                    dataGridView1.Rows[n].Cells[0].Value = m.Title;
                    dataGridView1.Rows[n].Cells[2].Value = m.Rating;
                    dataGridView1.Rows[n].Cells[3].Value = m.year;
                    dataGridView1.Rows[n].Cells[5].Value = GetFlagFile(m.flag);
                }
            }

This post has been edited by Andrew74: 26 June 2012 - 10:23 PM

[plh]

Why don't you comment out some of the if condition and set a breakpoint inside the if statement to see what condition is failing.

[sela007]

in order to add movie to datagrid all 3 checkboxes must be checked? is this true?

[tlhIn`toq]

Why are you mixing your & and && ?
& is a logical/binary additive
&& is 'and' as we humans think of it.
Looking at what you are doing I would be using all &&

Are you familiar with breakpoints and debugging and actually checking your values?

I have my doubts about this actually matching:
m.year.ToString() == domainUpDown1.SelectedItem.ToString()
at the very least I always talk my string comparrisons to lowercase to I am certain that don't fail from "June" != "june" etc.

I wonder about this too
m.Rating > double.Parse(domainUpDown2.SelectedItem.ToString()
because to use the greater than you would becomparing numeric values.
but one of these is a domainUpDown? What values does that hold?
How would a rating be greater than a domain name?

[Curtis Rutland]

Quote

& is a logical/binary additive
&& is 'and' as we humans think of it.

That's true if the values are numeric. If they evaluate to a boolean, & and && behave similarly with one crucial difference: & doesn't use short-circuit evaluation. & will always evaluate the right side of the equation, even if the left is already false.

Also, a DomainUpDown is like a numeric spinner, except for collections of strings or other objects. Domain means something different than domain name.

Now that that little tidbit is out of the way...

For the sake of all that's holy, don't do 1000 things in a single statement. It's impossible to debug, as you are learning. Your code will be easier to read if you just use variables to represent some of that, or better yet, most of that. Then, when it crashes out or you need to put a breakpoint on it, you can find the single exact operation that's failing.

While you're at it, name your controls something more intuitive as well. If I asked you in six months what "checkBox2" represented, you'd have no idea, I promise.

[tlhIn`toq]

Quote

Also, a DomainUpDown is like a numeric spinner, except for collections of strings or other objects. Domain means something different than domain name.

Right. But its a collection of strings so I wonder how the m.rating is going to be greater than the selected string. if (6 > "PG-13") or whatever just won't work.

Curtis is completely right about breaking down complex lines to simple ones to make debugging easier.

Q: I do x and y happens which I didn't expect but I don't know how to figure out why. How do I debug and find my problem?
A:

• Debugging video 1: Breakpoints and Local variables
  
• Debugging video 2: Advanced breakpoints
  
• Debugging tutorial
  
• Debugging tips
  
• Debugging in detail
  
• Great debugging tips
  
• It still doesn't work, article
  
• Debugging tools survival guide
  
• Video: Tips & Tricks to use Visual Studio to the fullest
  
  
  
• 5 return dataset.Tables[tableName].Columns.Count;
  A condensed line like this makes a lot of assuptions that everything goes right, and gives you nothing to check or debug.
  
  If only for R&D / Debug purposes it can often be advantagous to break down the line
  
  

  if (dataset != null)
  {
     if (datase.Tables != null)
     {
        if (!string.IsNullOrWhiteSpace(tableName)
        {
           if (dataset.Tables[tableName].Columns != null)
  

  
  
  Now you can put a breakpoint on the top line and walk through it with F10 and check every object. You also don't try to manipulate a thing that doesn't yet exist.