Get line below specific line in textBox multiline (c#)

Question

Hello everyone.  I want to find the value from texBox1 single line in textBox2 multiline and to get the line below the found line from textBox2 in textBox3.

For example:

If the content in a textBox2 multiline looks like this:

11111111111111
first name
22222222222222
second name
33333333333333
third name
44444444444444
fourth name
55555555555555
fifth name

If the value in textBox1 is:

3333333333333

I would like to get below line in textBox3 (the line from textBox2):

third name

I tried the following, see the code below. 

This code finds me that line from textBox1 to textBox2, but I need to get the line below the found line to texBox3. 

I am asking for your help. Thanks in advance.

private void searchlinebelow() 
{
  if (textBox2.Text != null)
                {
                    foreach (string line in textBox2.Lines)
                    {
                        if (line == textBox1.Text))
                        {
                            textBox3.Text = // Something like "line.ToString("\r\n");"
                            // In textBox3 I always want a line below "string line"
                        }
                    }
                }
   }

Answer 1

Hi @LeaV , Welcome to Microsoft Q&A,

You have multiple ways to do it, such as using string.split.

Here you can use textbox.lines.tolist() to directly convert the data into a list.

Then use indexof to know the corresponding position.

private void button1_Click(object sender, EventArgs e)
{
    List<string> list = new List<string>();
    list = textBox2.Lines.ToList();
    string SearchString = textBox1.Text;
    String result = "";
    foreach (string s in list)
    {
        if (s.Contains(SearchString))
        {
            result = list[list.IndexOf(s) + 1];
        }
    }
    textBox3.Text = result;
}

Best Regards,

Jiale

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Answer 2

foreach is a great method. However, in this case, I think it is better to enumerate using an index.

string[] lines = textBox2.Lines;
for (int i = 0; i < lines.Length; i++) {
    string line = lines[i];
    if (line == textBox1.Text) {
        if (i + 1 < lines.Length) {
            textBox3.Text = lines[i + 1];
            break;
        }
    }
}