Ext.Net 1.x_Ext.Net.控件空值校验提示

上图:

                                     <ext:DateField ID="txtStartDate" runat="server"  FieldLabel="开始时间"  EmptyText="--请选择起始时间--"  Width="250" LabelStyle="text-align:right"  BlankText="培训日期必填" AllowBlank="false">
                                      </ext:DateField>
                                       <ext:DateField ID="txtEndDate" runat="server"  FieldLabel="结束时间"  EmptyText="--请选择结束时间--"  Width="250" LabelStyle="text-align:right"  BlankText="培训日期必填" AllowBlank="false">
                                      </ext:DateField>
                                     <ext:Button ID="btnSumit" runat="Server" Text="查找"  Icon="Magnifier"    Width="80"  >
                                    <Listeners>
                                        <Click Handler="
                                            if (!#{txtStartDate}.validate()||!#{txtEndDate}.validate()) {
                                                Ext.Msg.alert('提醒','请选择培训的起始与结束时间！');
                                                // return false to prevent the btnLogin_Click Ajax Click event from firing.
                                                return false; 
                                            }" />
                                    </Listeners>

注意：AllowBlank="false