How do I prevent duplicate items in listbox1? C#

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C#

This code works well thanks to you.
How do I prevent duplicate items in listBox1?
What should I change the code below?

C#

listBox1.Items.AddRange(textBox2.Lines.Select(l => textBox1.Text + " " + l).ToArray());

What I have tried:

Something like:
listBox1.Items.AddRange(textBox2.Lines.Select(l => textBox1.Text + " " + l) && !listBox1.Items.Contains(textBox1.Text + " " + l)).ToArray());

Posted 4-Oct-16 3:55am

Member 10410972

Updated 4-Oct-16 4:37am

v2

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Richard MacCutchan 4-Oct-16 9:58am

You already have a suggestion in your original post.

2 solutions

Solution 2

While Karthik's code will work, it's better to remove duplicates from the input instead:

C#

IEnumerable<string> lines = textBox2.Lines.Distinct();
listBox1.Items.AddRange(lines.Select(l => textBox1.Text + " " + l).ToArray());

Posted 4-Oct-16 4:37am

OriginalGriff

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Member 10410972 4-Oct-16 11:21am

Thanks a lot.

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Karthik_Mahalingam · Accepted Answer · 2016-10-04T04:30:00

Solution 1

try this

C#

foreach (var item in textBox2.Lines.Select(l => textBox1.Text + " " + l).ToArray())
          {
              if (!listBox1.Items.Contains(item))
                  listBox1.Items.Add(item);
          }

Posted 4-Oct-16 4:30am

Karthik_Mahalingam

Comments

Member 10410972 4-Oct-16 11:25am

Thanks a lot. Works great!

Karthik_Mahalingam 5-Oct-16 0:39am

welcome :)