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>

此脚本位于cshtml razor视图中，进入视图模型为null，但我得到一个空引用异常：

异常详细信息：System.NullReferenceException：未将对象引用设置为对象的实例。

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 Line：22

为什么即使if条件为false，仍然会执行response.write，为什么异常指向第22行而不是第21行？

Answer 1

我没有MVC5来测试这个，但我认为你的Response对象是null，你应该创建这样的动态javascript：

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

此外，请确保Model.MessageText正确转义，以便其内容不会导致javascript错误。

Answer 2

由于您处于JS代码块中，因此您需要使用显式CSHTML开始标记来执行if。

内部语句如果条件为false则执行块执行

2 个答案: