Here you can search a text from a listbox, combobox or a multi line textbox.

Finding a particular string from a paragraph or from a list box is a common question arises in Visual Basic examination.

Search a string from paragraph of text

Here multiline textbox is used to type text and an input box accept search string. If the given string is found on the paragraph, then message box shows the result of search whether it is ‘Found’ or ‘Not found’.

   Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

Dim str As String

str = InputBox(“Enter the keyword to search”)

If TextBox1.Text.Contains(str) Then

MessageBox.Show(“Found”)

Else

MessageBox.Show(“Not found”)

End If

End Sub

Search and replace a string from paragraph of text

Here an input box accept a string for search and if the given string is found on the paragraph, then another input box ask the string to replace first one.

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click

Dim str As String
Dim replceStr As String

str = InputBox(“Enter the keyword to search for replace”)

If TextBox1.Text.Contains(str) Then

replceStr = InputBox(“Enter the word for replace”)

TextBox1.Text = TextBox1.Text.Replace(str, replceStr)

Else

MessageBox.Show(“Sorry, given string is not found”)

End If

End Sub

Searching an Item on List Box:

Here input box accept search text and a FOR loop continuously check every item on the listbox. The limit of the list box is the item count of the list box item. If an item matched with given search text, then a checker get a value 1 else the value will be 0. After the loop, program check the value of the checker variable. If it is 1, which means one of item matched.

Private Sub Button11_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button11.Click

Dim str As String
Dim i As Integer
Dim position as Integer
Dim checker As Integer = 0

str = InputBox(“Enter the keyword to search”)

For i = 0 To ListBox1.Items.Count – 1

If ListBox1.Items(i) = str Then

checker = 1

position = i + 1

Exit For

End If

Next

If checker = 1 Then
MessageBox.Show(“The string ” + str + ” is found at positoin: ” + position.ToString)
checker = 0
Else
MessageBox.Show(“Not Found”)
End If

End Sub

 

Position denotes the position of the search text on the list box.
You can use almost these same codes for searching an item from ComboBox. Note that all above codes are not optimized and not completely error free.