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What is the method for populating an array with selections from a listbox

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What is the method for populating an array with selections from a listbox

Sep 14th, 2009

I need to populate an array with the items a user has selected in a listbox.

Example: Listbox contains A, B, C, D, E
User selects B, D, E

create an array containing B, D, E

What method would I use to do this? I've found plenty of info for populating a listbox with the contents of an array, but not the other way around.

Thanks in advance for any help.

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Re: What is the method for populating an array with selections from a listbox

Sep 14th, 2009

try this:

 Help with Code Tags 
 C# Syntax (Toggle Plain Text) 
 
            int n = listBox1.SelectedItems.Count;
            string[] array = new string[n];
            for (int i = 0; i < n; i++)
            {
                array[i] = listBox1.SelectedValue.ToString();
            }
            int n = listBox1.SelectedItems.Count;
            string[] array = new string[n];
            for (int i = 0; i < n; i++)
            {
                array[i] = listBox1.SelectedValue.ToString();
            }

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Re: What is the method for populating an array with selections from a listbox

Sep 14th, 2009

Try this:

 Help with Code Tags 
 c# Syntax (Toggle Plain Text) 
// What I would do
            List<string> Strlist = new List<string>();
            foreach (string str in listBox1.SelectedItems)
            {
                Strlist.Add(str);
            }
 
            // Or try the corrected jatin24 style
            int n = listBox1.SelectedItems.Count; 
            string[] array = new string[n];
            for (int i = 0; i < n; i++)
            {
                array[i] = listBox1.SelectedItems[i].ToString();
            }
// What I would do
            List<string> Strlist = new List<string>();
            foreach (string str in listBox1.SelectedItems)
            {
                Strlist.Add(str);
            }

            // Or try the corrected jatin24 style
            int n = listBox1.SelectedItems.Count; 
            string[] array = new string[n];
            for (int i = 0; i < n; i++)
            {
                array[i] = listBox1.SelectedItems[i].ToString();
            }

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Re: What is the method for populating an array with selections from a listbox

Sep 14th, 2009

 Help with Code Tags 
 C# Syntax (Toggle Plain Text) 
string[] ar = listBox1.SelectedItems.Cast<string>().ToArray<string>();
string[] ar = listBox1.SelectedItems.Cast<string>().ToArray<string>();

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Re: What is the method for populating an array with selections from a listbox

Sep 14th, 2009

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Originally Posted by adatapost

Help with Code Tags

C# Syntax (Toggle Plain Text)
string[] ar = listBox1.SelectedItems.Cast<string>().ToArray<string>();
string[] ar = listBox1.SelectedItems.Cast<string>().ToArray<string>();

That is handy! For unboxing casts I have always used the .ConvertAll() but this is much easier to call

What I have been doing:

 Help with Code Tags 
 C# Syntax (Toggle Plain Text) 
double[] sArray2 = lst.ConvertAll<double>(new Converter<decimal, double>(Convert.ToDouble)).ToArray();
double[] sArray2 = lst.ConvertAll<double>(new Converter<decimal, double>(Convert.ToDouble)).ToArray();

Scott Knake
Custom Software Development
Apex Software, Inc.

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Re: What is the method for populating an array with selections from a listbox

Sep 14th, 2009

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Originally Posted by adatapost

Help with Code Tags

C# Syntax (Toggle Plain Text)
string[] ar = listBox1.SelectedItems.Cast<string>().ToArray<string>();
string[] ar = listBox1.SelectedItems.Cast<string>().ToArray<string>();

Wanted to +rep you, but I guess I already did somewhere and it wouldn't let me. Anyway, that is a very clean line of code I haven't seen before--kudos! I hope I remember it the next time I do that.

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Re: What is the method for populating an array with selections from a listbox

Sep 14th, 2009

mark as solved.

Due to lack of freedom of speech, i no longer post on this website.

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Re: What is the method for populating an array with selections from a listbox

Sep 14th, 2009

In terms of long lists and performance, Danny's solution is the best and to make it better use 'for' loop instead of 'foreach'
My test on 10000 items
Danny (for not foreach) | 39060 ticks
Danny | 48825 ticks
adatapost | 761670 ticks

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