ASP.Net 2.0中使用新的WebForm_DoPostBackWithOptions函数取代常规以前所使用的__doPostback函数
ASP.Net 2.0中使用新的WebForm_DoPostBackWithOptions函数取代常规以前所使用的__doPostback函数
(本文来自ASP.NET 2.0中实现跨页面提交)
当设置了Button控件的PostBackUrl属性之后,ASP.NET运行时将为按钮控件的所对应的的html元素绑定一段新的JavaScript代码。使用新的 WebForm_DoPostBackWithOptions函数取代常规以前所使用的__doPostback函数。具体的HTML代码示例如下:
<input type="submit" name="Button2" value="Postback to Second Page" onclick="javascript:WebForm_DoPostBackWithOptions(new WebForm_PostBackOptions("Button2", "", false, "", "SecondPage.aspx", false, false))" id="Button2" />
上述代码中的WebForm_DoPostBackWithOptions函数与WebForm_PostBackOptions函数的javascript代码如下:
function WebForm_PostBackOptions(eventTarget, eventArgument, validation, validationGroup, actionUrl, trackFocus, clientSubmit) {
this.eventTarget = eventTarget;
this.eventArgument = eventArgument;
this.validation = validation;
this.validationGroup = validationGroup;
this.actionUrl = actionUrl;
this.trackFocus = trackFocus;
this.clientSubmit = clientSubmit;
}
function WebForm_DoPostBackWithOptions(options) {
var validationResult = true;
if (options.validation) {
if (typeof(Page_ClientValidate) == 'function') {
validationResult = Page_ClientValidate(options.validationGroup);
}
}
if (validationResult) {
if ((typeof(options.actionUrl) != "undefined") && (options.actionUrl != null) && (options.actionUrl.length > 0)) {
theForm.action = options.actionUrl;
}
if (options.trackFocus) {
var lastFocus = theForm.elements["__LASTFOCUS"];
if ((typeof(lastFocus) != "undefined") && (lastFocus != null)) {
if (typeof(document.activeElement) == "undefined") {
lastFocus.value = options.eventTarget;
}
else {
var active = document.activeElement;
if ((typeof(active) != "undefined") && (active != null)) {
if ((typeof(active.id) != "undefined") && (active.id != null) && (active.id.length > 0)) {
lastFocus.value = active.id;
}
else if (typeof(active.name) != "undefined") {
lastFocus.value = active.name;
}
}
}
}
}
}
if (options.clientSubmit) {
__doPostBack(options.eventTarget, options.eventArgument);
}
}
this.eventTarget = eventTarget;
this.eventArgument = eventArgument;
this.validation = validation;
this.validationGroup = validationGroup;
this.actionUrl = actionUrl;
this.trackFocus = trackFocus;
this.clientSubmit = clientSubmit;
}
function WebForm_DoPostBackWithOptions(options) {
var validationResult = true;
if (options.validation) {
if (typeof(Page_ClientValidate) == 'function') {
validationResult = Page_ClientValidate(options.validationGroup);
}
}
if (validationResult) {
if ((typeof(options.actionUrl) != "undefined") && (options.actionUrl != null) && (options.actionUrl.length > 0)) {
theForm.action = options.actionUrl;
}
if (options.trackFocus) {
var lastFocus = theForm.elements["__LASTFOCUS"];
if ((typeof(lastFocus) != "undefined") && (lastFocus != null)) {
if (typeof(document.activeElement) == "undefined") {
lastFocus.value = options.eventTarget;
}
else {
var active = document.activeElement;
if ((typeof(active) != "undefined") && (active != null)) {
if ((typeof(active.id) != "undefined") && (active.id != null) && (active.id.length > 0)) {
lastFocus.value = active.id;
}
else if (typeof(active.name) != "undefined") {
lastFocus.value = active.name;
}
}
}
}
}
}
if (options.clientSubmit) {
__doPostBack(options.eventTarget, options.eventArgument);
}
}
用户点击按钮时,当前表单将内容提交给PostPageUrl属性所指定的目标页面。当页面中含有可以实现跨页面提交功能的控件时,页面会创建一个name为__PREVIOUSPAGE的隐藏字段,此字段包含了源页面的信息。目标页面则使用此信息来创建一个完整状态的引用来调用源页面对象。上述隐藏字段的相关HTML代码示例如下:
<input type="hidden" name="__PREVIOUSPAGE" id="__PREVIOUSPAGE" value="ND3_1GqjDSUeAC3yLYVz-eQrkTzZLYFHliIFf7mMQVBdmwZmFi8HG4mzX5pfZY0n0" />