添加和QUOT;的onclick＆QUOT;归因于ASP.NET的DropDownList项目 [英] Adding "onclick" attribute to asp.net dropdownlist item

问题描述

我可以在一个单选按钮列表项的属性添加到项目像这样：

I can add an attribute to items in a RadioButtonList item like so:

PaymentMethodDropDownList.Items[0].Attributes.Add("onclick", "javascript:showNoMethods();");
PaymentMethodDropDownList.Items[1].Attributes.Add("onclick", "javascript:showCreditCardMethod();");
PaymentMethodDropDownList.Items[2].Attributes.Add("onclick", "javascript:showSendPaymentMethod();");

然而，当我试图将属性添加到DropDownList控件它似乎并没有工作。我希望它是相似的。

However, when I try to add the attributes to a DropDownList control it doesn't seem to work. I would expect it to be similar.

推荐答案

这不能以同样的方式作为一个RadioButtonList的完成，为一个DropDownList，正确的属性事件名称是onchange事件，而不是onclick事件。
该事件应附DropDownList的本身，而不是项目如下：

This cannot be done in the same way as a radioButtonList, for a dropdownlist, the correct attribute event name is "onchange" instead of "onclick". The event should be attached to DropDownList Itself and not the items as follows:

PaymentMethodDropDownList.Attributes.Add("onchange",
                                            "showCreditCardMethod();");

此外，这是有点更复杂，更需要自定义javascript函数根据所选择的选项来执行不同的操作。这里有一个例子：

Also, this is a little bit more complicated and requires a custom javascript function to perform a different action depending on the option selected. Here's an example:

PaymentMethodDropDownList.Attributes.Add("onchange",
                                             "handleDropDownEvents(this);");

自定义JavaScript函数：这个假设的下拉列表项的值是信用卡式和SendPayment

Custom Javascript function: this assumes that values for the dropdown items are "CreditCard" and "SendPayment".

<script type="text/javascript">
    function handleDropDownEvents(e){
      if(e.value == "CreditCard"){
         showCreditCardMethod();
      }
      else if(e.value == "SendPayment"){
        showSendPaymentMethod();
      }
    }
</script>

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