how to make a datatable without case sensitive and show the result with only 4-5 char

I've a filter, a datatable linked with a listbox and if statements, now i need to know, how can i say to program, when user search on datatable to don't care if a word is written with an upcase or lowcase character, and show the result when a few words at least is written into texbox? (like 4 or 5)

This is the code:

Code:

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Private Sub TextBox1_TextChanged(sender As Object, e As EventArgs) Handles TextBox1.TextChanged
        Dim dvtest As New DataView
        dvtest = dttest.DefaultView
        dvtest.RowFilter = "test Like '%" + TextBox1.Text + "%'"
        If dttest.Rows.Count >0 <2 Then
            For counter As Integer = 0 To dttest.Rows.Count < 3
                If dttest.Rows(0).Item(0).ToString = TextBox1.Text Then
.....
End If

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UPDATE
I resolved it with this code, wasn't very hard sorry:

Code:

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TextBox1.Text = Globalization.CultureInfo.CurrentCulture.TextInfo.ToTitleCase(TextBox1.Text)
        TextBox1.SelectionStart = TextBox1.TextLength

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Now i want to know, how i can show the result of an if statement with at least 2 or 5 words without trim the left text ? I tried with this code:

Code:

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dttest.Rows(0).Item(0).ToString.ToLower.StartsWith(TextBox1.Text.ToLower)

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But with this, the Item of that row disappear, and only with a letter(wrong one), show the picture of that if(but i like the user just put 3 or 4 words for show the result of the if (the same of that row value without trim the others, to show the picture)

The String.Equals, String.StartsWith and String.EndsWith methods are all overloaded and allow you to specify whether the comparison should be case-sensitive or case-insensitive. You never need to change the case of anything in order to compare.

For the originally asked question see: DataTable.CaseSensitive Property