如果條件為false時，if語句仍在執行的語句

Question

@model Portal.Models.MessageModel

<link href="~/Content/jquery.wysiwyg.css" rel="stylesheet" />
<script type="text/javascript" src="~/Scripts/jquery-2.0.3.js"></script>
<script src="~/Scripts/jquery-migrate-1.2.1.js"></script>
<script src="~/scripts/jquery.unobtrusive-ajax.js"></script>
<script type="text/javascript" src="~/Scripts/jquery.wysiwyg.js"></script>
<script type="text/javascript" src="~/Scripts/wysiwyg-controls/wysiwyg.image.js"></script>
<script type="text/javascript" src="~/Scripts/wysiwyg-controls/wysiwyg.link.js"></script>
<script type="text/javascript" src="~/Scripts/wysiwyg-controls/wysiwyg.table.js"></script>
<script type="text/javascript" src="~/Scripts/wysiwyg-controls/wysiwyg.cssWrap.js"></script>
<script type="text/javascript" src="~/Scripts/wysiwyg-controls/wysiwyg.colorpicker.js"></script>

<script type="text/javascript">
    (function($) {
        $(document).ready(function() {
            $('#messagearea').wysiwyg({
                initialContent: function () {
                    var inittext = "";
                    @{if (Model != null)
                       {
                           <text>inittext = '@Model.MessageText';</text>
                       }
                    }
                        return inittext;
                }
            });
        });
    })(jQuery);
</script>
    <table id="compose-table" style="border-spacing:0 0; max-width: 1200px; min-width: 450px;box-shadow: 0 0 5px 2px #cfcfcf; width:auto; background-color:white">
        <tbody>
            <tr >
                <td style="box-shadow: inset 0 0 10px #383838;">
                    <form>
                        <div id="destinations" style="border-bottom: 1px solid #cfcfcf; padding: 12px 1px 12px 2px; ">                            

                            **<input name="to" spellcheck="false" autocomplete="false" autocapitalize="false" autocorrect="off" style="padding-left: 8px; background-color:transparent; width:1078px; resize:none; border: none;" placeholder="To" onfocus="displayCCandBCC" value="@Model.From"/>**
                        </div>
                        <div id="addressdiv" style="display: none">
                            <table>
                                <tbody>
                                    <tr id="cc" style="display: none"></tr>
                                    <tr id="bcc" style="display: none"></tr>
                                </tbody>
                            </table>
                        </div>

                        <div id="subjectdiv" style="border-bottom: 1px solid #cfcfcf; padding : 12px 1px 12px 2px; ">
                        @{if (Model == null){
                            <input name="subject" style="padding-left: 8px; width: 1078px; border: none; background-color: inherit" placeholder="Subject" />
                          }
                          else
                          {
                            <input name="subject" style="padding-left: 8px; width: 1078px; border: none; background-color: inherit" placeholder="Subject" value="@String.Concat("re: ", Model.Subject)" />
                          }
}
                        </div>
                        <textarea id="messagearea" style="min-height:300px; width:100%; padding:0 0 0 0"></textarea>
                    </form>
                </td>
            </tr>
        </tbody>
</table>

此腳本位於cshtml剃刀視圖中，進入視圖Model為null，但出現空引用異常：

異常詳細信息：System.NullReferenceException：對象引用未設置為對象的實例。

Source Error: 

Line 20:       {
Line 21:           Response.Write("inittext = '@Model.MessageText';");
Line 22:       }
Line 23:       return inittext;
Line 24:   }

源文件：d：\\ Projects \\ Patient Portal \\ Portal.MVC \\ Views \\ Message \\ Compose.cshtml行：22

為什么即使if條件為false，response.write仍在執行，為什么異常指向第22行而不是第21行？

Answer 1

我沒有MVC5對此進行測試，但我認為您的Response對象為null，您應該像這樣創建動態javascript：

@if (Model != null)
{
    <text>inittext = '@Model.MessageText';</text>
}

另外，請確保Model.MessageText正確轉義，以便其內容不會引起JavaScript錯誤。

Answer 2

由於您處於JS代碼塊中，因此需要使用顯式的CSHTML開頭標記來進行if操作。