ASP.Net Validation not allowing to submit in MultiView control in ASP.Net

You need to give the ValidationGroup.

HTML:

<form id="form1" runat="server">
<div>
    <table border="1" cellpadding="2" cellspacing="3" width="500">
        <tr>
            <td>
                <asp:LinkButton ID="lnkTab1" runat="server" OnClick="View1Show" Text="Tab1"></asp:LinkButton>
            </td>
            <td>
                <asp:LinkButton ID="lnkTab2" runat="server" OnClick="View2Show" Text="Tab2"></asp:LinkButton>
            </td>
            <td>
                <asp:LinkButton ID="lnkTab3" runat="server" OnClick="View3Show" Text="Tab3"></asp:LinkButton>
            </td>
        </tr>
        <tr>
            <td colspan="3">
                <asp:MultiView ID="MultiView1" runat="server">
                    <table width="100%" cellpadding="2" cellspacing="5">
                        <tr>
                            <td>
                                <asp:View ID="View1" runat="server">
                                    Name
                                    <br />
                                    <asp:TextBox ID="txtName" runat="server" />
                                    <asp:RequiredFieldValidator ID="rfvName" runat="server" ControlToValidate="txtName"
                                        ValidationGroup="MultiView1" ErrorMessage="Please enter value">
                                    </asp:RequiredFieldValidator>
                                </asp:View>
                            </td>
                            <td>
                                <asp:View ID="View2" runat="server">
                                    Phone
                                    <br />
                                    <asp:TextBox ID="txtPhone" runat="server" />
                                    <asp:RequiredFieldValidator ID="rfvPhone" runat="server" ControlToValidate="txtPhone"
                                        ValidationGroup="MultiView1" ErrorMessage="Please enter value">
                                    </asp:RequiredFieldValidator></asp:View>
                            </td>
                            <td>
                                <asp:View ID="View3" runat="server">
                                    City
                                    <br />
                                    <asp:TextBox ID="txtCity" runat="server" />
                                    <asp:RequiredFieldValidator ID="rfvCity" runat="server" ControlToValidate="txtCity"
                                        ValidationGroup="MultiView1" ErrorMessage="Please enter value">
                                    </asp:RequiredFieldValidator></asp:View>
                            </td>
                        </tr>
                    </table>
                </asp:MultiView>
            </td>
        </tr>
        <tr>
            <td colspan="3" align="center">
                <asp:Button Text="Save" runat="server" ValidationGroup="MultiView1" OnClick="Save" />
            </td>
        </tr>
    </table>
</div>
</form>

C#:

protected void View1Show(object sender, EventArgs e)
{
    MultiView1.ActiveViewIndex = 0;
}
protected void View2Show(object sender, EventArgs e)
{
    MultiView1.ActiveViewIndex = 1;
}
protected void View3Show(object sender, EventArgs e)
{
    MultiView1.ActiveViewIndex = 2;
}

protected void Save(object sender, EventArgs e)
{
    string name = this.txtName.Text.Trim();
    string phone = this.txtPhone.Text.Trim();
    string city = this.txtCity.Text.Trim();
}

Thank You.