convert textbox to string

how can i convert textbox to string and to make it upper case?? here is my code.. please help..

VB Code:

Dim TextBox1 As String
        Dim a As New DataSet
        Dim b As New OleDb.OleDbDataAdapter
        Dim c As New OleDb.OleDbConnection
        c.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\phil\wa.mdb;Persist Security Info=true"
        c.Open()
        b.SelectCommand = New OleDb.OleDbCommand("SELECT * FROM Table1 WHERE Fname=" & TextBox1 & ";", c)
        TextBox1.ToUpper()
        b.Fill(a, "Hello")
        DataGrid1.DataSource = a.Tables(0)
        DataGrid1.DataBind()
        c.Close()

Code:

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b.SelectCommand = New OleDb.OleDbCommand("SELECT * FROM Table1 WHERE Fname=" & TextBox1.Text.ToUpper & ";", c)

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