Question

我在ASP.NET中遇到了回调和多选select控件。正如我所注意到的，微软自2006年以来就有一个错误（！），当我在选择1,2,3的多选中执行回调时，回发数据为1,1,1。我已经确定了问题，它采用以下方法：

function WebForm_InitCallback() {
    var formElements = theForm.elements,
        count = formElements.length,
        element;
    for (var i = 0; i < count; i++) {
            element = formElements[i];
            var tagName = element.tagName.toLowerCase();
            if (tagName == "input") {
                var type = element.type;
                if ((__callbackTextTypes.test(type) || ((type == "checkbox" || type == "radio") && element.checked))
                && (element.id != "__EVENTVALIDATION")) {
                    WebForm_InitCallbackAddField(element.name, element.value);
                }
            }
        else if (tagName == "select") {
            var selectCount = element.options.length;
                for (var j = 0; j < selectCount; j++) {
                var selectChild = element.options[j];
                if (selectChild.selected == true) {
                    WebForm_InitCallbackAddField(element.name, element.value);
                }
            }
        }
        else if (tagName == "textarea") {
            WebForm_InitCallbackAddField(element.name, element.value);
        }
    }
}

element.value未传递正确的值，但{＆＃34}中的selectedChild.value选择＆＃34;标签

即使我发现了问题，并且我知道如何覆盖此方法，但我并不相信这会有效。覆盖来自资源的JavaScript方法是否正确？你建议我这样做吗？

感谢。

Answer 1

该代码被Microsoft视为遗留代码，除非他们认为这是一个关键问题，否则不会修复。

他们的解决方法是在将代码发送到浏览器之前实现自定义http模块以更正代码。

创建自定义http模块
实施ReleaseRequestState事件

将以下代码放在那里：

void context_ReleaseRequestState(object sender, EventArgs e)
{
    HttpApplication application = sender as HttpApplication;

    if (application != null)
    {
        if (application.Request.Url.ToString().Contains("WebResource.axd"))
        {
            #region Set private value of HttpWriter so we can write to output stream
            //See http://daniel-richardson.blogspot.com/2008/11/how-to-apply-filter-to-content-returned.html
            var response = application.Context.Response;
            var httpWriterField = typeof(HttpResponse).GetField("_httpWriter",
                                 BindingFlags.NonPublic | BindingFlags.Instance);
            var ignoringFurtherWritesField = typeof(HttpWriter).GetField("_ignoringFurtherWrites",
                                             BindingFlags.NonPublic | BindingFlags.Instance);
            var httpWriter = httpWriterField.GetValue(response);
            ignoringFurtherWritesField.SetValue(httpWriter, false);
            #endregion

            //We need to read filter property first or we get exception
            var f = application.Response.Filter;

            application.Response.Filter = new ResponseFilter(application.Response.OutputStream);
        }
    }
}

创建继承自Stream类。

构造

public ResponseFilter(Stream responseStream)
    {
        ResponseStream = responseStream;
    }

写方法：

    public override void Write(byte[] buffer, int offset, int count)
    {
        string output = Encoding.UTF8.GetString(buffer, offset, count);

        string fixedOutput = output.Replace(@"if (selectChild.selected == true) {
                WebForm_InitCallbackAddField(element.name, element.value);", "if (selectChild.selected == true) {WebForm_InitCallbackAddField(element.name, selectChild.value);");

        byte[] fixedBuffer = Encoding.UTF8.GetBytes(fixedOutput);


        ResponseStream.Write(fixedBuffer, 0, fixedBuffer.Length);
    }

- 实现其他abtract方法时，只需简单地调用ResponseStream的方法

source

覆盖WebResource javascript方法 - WebForm_InitCallback（）

1 个答案: