两个String一模一样,竟不相同!大虾帮帮忙啊

一段程序
TextBox2的TextMode是password
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Try
            Me.SqlCommand1.CommandText = "SELECT ClientCash.* FROM ClientCash where 帐号=" + TextBox1.Text
            SqlDataAdapter1 = New System.Data.SqlClient.SqlDataAdapter(SqlCommand1)
            DataSet1 = New System.Data.DataSet
            SqlDataAdapter1.Fill(DataSet1, "ClientCash")
        Catch ex As Exception
            Response.Write("<script language=javascript>alert('帐号错误!请重新输入')</script>")
        End Try
        Response.Write(DataSet1.Tables(0).Rows(0).Item(1).ToString)
        Response.Write(TextBox2.Text)
        If TextBox2.Text.Equals(DataSet1.Tables(0).Rows(0).Item(1).ToString) Then
            Label3.Text = "余额为" + DataSet1.Tables(0).Rows(0).Item(2).ToString()
        Else
            Response.Write("<script language=javascript>alert('密码错误!')</script>")
        End If    End Sub
Response.Write(DataSet1.Tables(0).Rows(0).Item(1).ToString)
和
Response.Write(TextBox2.Text)
输出结果一样
但后面的If TextBox2.Text.Equals(DataSet1.Tables(0).Rows(0).Item(1).ToString)死活通不过
用TextBox2.Text=DataSet1.Tables(0).Rows(0).Item(1).ToString,
StrComp(TextBox2.Text,DataSet1.Tables(0).Rows(0).Item(1).ToString)=0
String.Eqauls(TextBox2.Text,DataSet1.Tables(0).Rows(0).Item(1).ToString)都通不过
究竟怎么回事呢