使用JavaScript返回SharePoint 2013当前用户

Question

我想学习如何从一个函数返回值，然后在另一个函数中使用它。我可以在div中显示该值，也可以在警报窗口中获取它，但是我需要在其他函数中使用该值。

<script type="text/javascript">

    SP.SOD.executeOrDelayUntilScriptLoaded(testCase,"sp.js");

    function showUserInfo(){
        var clientContext = SP.ClientContext.get_current();
        var user = clientContext.get_web().get_currentUser();
        clientContext.load(user);
        clientContext.executeQueryAsync(function(){
            return user.get_loginName();
        },function(sender,args){alert(args.get_message());})
    }


    function testCase() {
      var test = showUserInfo(); 
      alert(test);
    }

</script>

Answer 1

如果您需要支持Internet Explorer

要支持Internet Explorer，应使用类似于@Amos_MSFT建议的回调函数。在下面，您将找到我的解决方案，该解决方案与@Amos_MSFW发布的解决方案非常相似，但有一些区别和注释。

// Execute the testCase() function only after sp.js has loaded and is ready.
SP.SOD.executeFunc('sp.js', 'SP.ClientContext', function() {
  textCase();
});

function testCase() {
  getLoginName(function(error, success) {
    if (error) {
      alert(error);
    } else {
      /*
       * The line below is not really necessary, as the result of the
       * getLoginName() function is already available in the success
       * variable.  You can already pass it to other functions, like
       * this: alert(success);
       */
      var loginName = success;
      alert(loginName);
    }
  });
}

function getLoginName(callback) {
  var clientContext = SP.ClientContext.get_current();
  var user = clientContext.get_web().get_currentUser();

  clientContext.load(user);
  clientContext.executeQueryAsync(
    function() {
      /*
       * The first argument of the callback() function is used for the
       * error message, so we need to use null as the first argument
       * when we want to return the login name as the success message.
       */
      callback(null, user.get_loginName());
    },
    function(_sender, args) {
      callback(args.get_message());
    }
  );
}

如果不需要支持Internet Explorer，则

我建议您在不需要支持Internet Explorer的情况下使用Promise。 Promise是一种特殊的对象，代表尚未完成的操作，它们使异步操作的工作变得轻松而有趣。我不够流利，无法详细解释它们，因此，如果您有兴趣，建议您阅读上面链接的文章。不过，我将告诉您的是，我们可以使用Promise来确保testCase()功能停止并等待showUserInfo()功能完成，就像在等待登录名可用一样。

我还没有机会测试下面的代码，但是应该可以。如果没有，请告诉我。如果您对Promises还不熟悉，我还添加了一些评论。

const showUserInfo = () => {
  return new Promise((resolve, reject) => {
    const clientContext = SP.ClientContext.get_current();
    const currentUser = clientContext.get_web().get_currentUser();

    clientContext.load(currentUser);
    clientContext.executeQueryAsync(
      () => {
        /*
         * We resolve the Promise when the query has executed successfully.
         * Resolving a Promise means marking it as fullfilled, or complete, and
         * returning the current user's login name.
         */
        resolve(currentUser.get_loginName());
      },
      (_sender, args) => {
        /*
         * If something goes wrong, we reject the Promise.  Rejecting means
         * marking it as failed, while still returning something.  In this
         * case, we return the error message.
         */
        reject(args.get_message());
      }
    );
  });
}

const testCase = async () => {
  /*
   * We use the await keyword to halt the code and wait for the showUserInfo()
   * function to finish.  What really happens is that we wait for the Promise
   * in the showUserInfo() function to be marked as settled, whether it is
   * fullfilled or rejected, and then assign the result to the test constant.
   */
  const test = await showUserInfo();
  alert(test);
}

SP.SOD.executeOrDelayUntilScriptLoaded(testCase, 'sp.js');

Answer 2

函数executeQueryAsync是异步的。您可以使用回调函数获取返回值。示例代码供您参考：

    <script type="text/javascript">
SP.SOD.executeFunc('sp.js', 'SP.ClientContext', function(){
  var testCase=function(callback){                             
        var clientContext = SP.ClientContext.get_current();
        var user = clientContext.get_web().get_currentUser();
        clientContext.load(user);
        clientContext.executeQueryAsync(function(){                            
                                callback(null,user.get_loginName()) ;          
        },function(sender,args){alert(args.get_message());})
    }

    testCase(function(error,name){
                if (error) {
    console.error(error);
    return;
  }
  console.log(name);       
                }) 
});
</script>