Search through text file and return a line of text - vb.net

Question

I am trying to create a program that will search a text file for a line of text and then return the full line of information.
Example line: Joe Blogs JBL 1234
Search: Joe Blogs
Search returns: Joe Blogs JBL 1234
To make it as simple as possible, I have 2 text boxes & 1 button.
Textbox1 = search
Textbox2 = Search results
Button = Search button
Can anyone tell me how to do this because I'm finding it really difficult. I'm new to VB coding so the simplest of code would be helpful!
This is what I have so far:
Imports System.IO
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
' Input Text Error
If TextBox1.TextLength = 0 Then
MsgBox("Please enter a Staff Name or Staff Code", MsgBoxStyle.Information, "Error")
End If
'Perform Search
Dim strText As String = SearchFile("F:\Documents\Documents\Visual Studio 2015\Projects\ExtentionLocator\ExtentionLocator\Extentionlist.txt", TextBox1.Text)
If strText <> String.Empty Then
TextBox2.Text = strText
End If
End Sub
'Search Function
Public Shared Function SearchFile(ByVal strFilePath As String, ByVal strSearchTerm As String) As String
Dim sr As StreamReader = New StreamReader(strFilePath)
Dim strLine As String = String.Empty
Try
Do While sr.Peek() >= 0
strLine = String.Empty
strLine = sr.ReadLine
If strLine.Contains(strSearchTerm) Then
sr.Close()
Exit Do
End If
Loop
Return strLine
Catch ex As Exception
Return String.Empty
End Try
End Function
'Clear Button
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
TextBox2.Text = ""
TextBox1.Text = ""
End Sub
' Open The text file
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
Process.Start("C:\Users\kylesnelling\Documents\Visual Studio 2015\Projects\ExtentionLocator\ExtentionLocator\Extentionlist.txt")
End Sub
End Class
Whenever I perform a search, all I get back is the last line of the text file... does anyone know why?

Answer 1

As Alex B has stated in comments, line If strLine.Contains("textbox1.text") should be If strLine.Contains(strSearchTerm)
Also you are not passing in the search item to the function. The below line you have passed in the string textbox1.text as a string rather than the text inside the textbox. Hence why you never find the line you are searching for and always returns the last record of your file.
Dim strText As String = SearchFile("F:\Documents\Documents\Visual Studio 2015\Projects\ExtentionLocator\ExtentionLocator\Extentionlist.txt", "textbox1,text")
This line should be:
Dim strText As String = SearchFile("F:\Documents\Documents\Visual Studio 2015\Projects\ExtentionLocator\ExtentionLocator\Extentionlist.txt", textbox1.text)
Also with this line Dim sr As StreamReader = New StreamReader("F:\Documents\Documents\Visual Studio 2015\Projects\ExtentionLocator\ExtentionLocator\Extentionlist.txt") why have you used the same path destination when you have already passed in this file location in the variable strFilePath.
line should be Dim sr As StreamReader = New StreamReader(strFilePath)
Its best to use the variables being passed into the function otherwise this function won't be very useful to other parts of code that may be referencing it or if search terms or filepaths change.
Updated from comments:
strLine.ToUpper.Contains(strSearchTerm.ToUpper) this line will make both text uppercase and the word you are searching for to uppercase, which will allow them to ignore case sensitivity, so for example, "text" can match with "Text" by both being converted to "TEXT" when used to compare.

Answer 2

Give this a try friend.
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim searchResult As String = SearchFile("F:\Documents\Documents\Visual Studio 2015\Projects\ExtentionLocator\ExtentionLocator\Extentionlist.txt", _
"text to search for")
Me.TextBox2.Text = searchResult
End Sub
Public Shared Function SearchFile(ByVal strFilePath As String, ByVal strSearchTerm As String) As String
Dim fs As New System.IO.StreamReader(strFilePath)
Dim currentLine As String = String.Empty
Try
Dim searchResult As String = String.Empty
Do While fs.EndOfStream = False
currentLine = fs.ReadLine
If currentLine.IndexOf(strSearchTerm) > -1 Then
searchResult = currentLine
Exit Do
End If
Loop
Return searchResult
Catch ex As Exception
Return String.Empty
End Try
End Function