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Sep 14th, 2009

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

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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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Cory_Brown

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Sep 14th, 2009

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

try this:

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();
            }

jatin24

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Sep 14th, 2009

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

Try this:

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();
            }

ddanbe

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Sep 14th, 2009

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

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

adatapost

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Sep 14th, 2009

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

Click to Expand / Collapse Quote originally posted by adatapost ...

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:

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();

sknake

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Sep 14th, 2009

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

Click to Expand / Collapse Quote originally posted by adatapost ...

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.

DdoubleD

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Posting Shark

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Sep 14th, 2009

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

mark as solved.

serkan sendur

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Sep 14th, 2009

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

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

Ramy Mahrous

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Sep 14th, 2009

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

Thank you all for the responses. Marked as solved.

Cory_Brown

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