how to disable another dropdown if text in dropdown list is select in ASP.Net

Refer the below code.

protected void OnChange(object sender, EventArgs e)
{
    if (DDlLoanType.Text.ToLower() != "select" || DDlLoanType.SelectedValue.ToLower() != "select")
    {
        DdlTerm.Enabled = true;
        string query = "select LoanTerm, LoanRate from  LoanRates where LoanType = '" + DDlLoanType.Text;
        BindDropDownList(DdlTerm, query, "LoanTerm", "LoanRate", "Select");
    }
    else
    {
        DdlTerm.Enabled = false;
    }
}

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