从ASP.NET背后的代码中调用Javascript函数
[英]Calling Javascript function from code behind ASP.NET
问题描述
I'm attempting to call a javascript method in its own file from code behind on a button click. 
我试图通过单击按钮后的代码在其自己的文件中调用javascript方法。
aspx file aspx文件
protected void Next_Click(object sender, EventArgs e)
{
if (hidden.Value == "")
{
Response.Write(@"<script language='javascript'>drawImage();</script>");
}
}
js file js文件
function drawImage() {
context.drawImage(video, 0, 0, 320, 240);
var imgBase = canvas.toDataURL('image/jpeg');
document.getElementById("hidden").value = imgBase;
}
The problem is that this wont call the draw image method, i suspect it's cause the js file is its own file but i'm not sure. 问题是，这不会调用draw image方法，我怀疑这是因为js文件是其自己的文件，但我不确定。
Any help you could give would be greatly appreciated. 您能提供的任何帮助将不胜感激。
3 个解决方案
解决方案1
1 已采纳 2014-05-14 13:15:41
see http://msdn.microsoft.com/de-de/library/z9h4dk8y.aspx 参见http://msdn.microsoft.com/de-de/library/z9h4dk8y.aspx
try this 尝试这个
string jquery = "drawImage();"
ClientScript.RegisterStartupScript(typeof(Page), "a key",
"<script type=\"text/javascript\">"+ jquery +"</script>"
);
解决方案2
0 2013-05-07 04:12:02
I presume you already included the script file in your page. 我想您已经在页面中包含了脚本文件。
If you require the postback, you need ClientScriptManager.RegisterStartupScript Method (Type, String, String, Boolean) .. 如果需要回发，则需要ClientScriptManager.RegisterStartupScript方法（类型，字符串，字符串，布尔值） 。
protected void Next_Click(object sender, EventArgs e)
{
if (hidden.Value == "")
{
ClientScriptManager cs = Page.ClientScript;
cs.RegisterStartupScript(this.GetType(), 'startupScript', 'drawImage();', true);
}
}
You can call the function from your button itself, without the postback. 您可以从按钮本身调用该函数，而无需回发。
<asp:Button runat="server" ID='next' OnClientClick="return drawImage();" />
and in the script 并在脚本中
function drawImage() {
if(document.getElementById("hidden").value != undefined || document.getElementById("hidden").value != "")
{
context.drawImage(video, 0, 0, 320, 240);
var imgBase = canvas.toDataURL('image/jpeg');
document.getElementById("hidden").value = imgBase;
return false;
}
}
解决方案3
0 2013-05-07 04:17:08
1). 1）。 If the function is stored in external file (eg MyScript.js ) then you should include it in the <head> section of the web page and add onclick event to the button, like: 如果函数存储在外部文件（例如MyScript.js ）中，则应将其包含在网页的<head>部分中，然后将onclick事件添加到按钮，例如：
ButtonName.Attributes.Add("onclick", {YourFunction});
in Page_Load event. 在Page_Load事件中。
2) Another approach is to assign the entire javascript function to a string variable and then pass it instead of {YourFunction} prefixed with javascript: . 2）另一种方法是将整个javascript函数分配给一个字符串变量，然后将其传递，而不是以javascript:为前缀的{YourFunction}。 In this case you don't even need the external file. 在这种情况下，您甚至不需要外部文件。
Hope it will help. 希望它会有所帮助。 My best, Alex 我最好的Alex
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