Question

以json为对象很容易，但是不知道我的代码发生了什么。

所以我想使用PHP读取图像元数据（最重要的是图像创建的日期时间），但是iPhone和其他电话不发送带有图像的此信息，如果尝试使用PC上载则可以正常工作。但是如果图像被压缩，那么我们将丢失所有元数据。

因此，使用php读取元数据并没有用，然后我决定通过JavaScript进行读取，因此我使用的是exif.js。

对于多次上传，一切正常，但是当我尝试将对象转换为json时，我得到的是空字符串。

这是我的代码

Sub CreateAndNameWorksheets()
Dim c As Range
Dim ws As Worksheet: Set ws = Sheets("List")
Dim sh As Worksheet
Dim FoundSh As Boolean

Application.ScreenUpdating = False
LastRow = ws.Cells(ws.Rows.Count, "B").End(xlUp).Row
'get last row with data on Column B
For Each c In ws.Range("B5:B" & LastRow) 'loop through row 1 to Last

    For Each sh In ThisWorkbook.Worksheets 'loop through Worksheets
        If c.Value = sh.Name Then FoundSh = True 'if it exists set flag as found
    Next sh

    If FoundSh = False Then 'if it wasn't found then create it
        Sheets("Template").Copy After:=Sheets(Sheets.Count)
        With c
            ActiveSheet.Name = .Value
           .Parent.Hyperlinks.Add Anchor:=c, Address:="", SubAddress:= _
                "'" & .Text & "'!A1", TextToDisplay:=.Text
        End With
    End If
    FoundSh = False 'reset flag for next loop
Next c
Application.ScreenUpdating = True

Call SheetKiller
Call Test

End Sub



Sub SheetKiller()

Dim rList As Range, s As String, sh As Worksheet
Dim KillIt As Boolean, r As Range
Sheets("List").Activate
Set rList = Range("B1:B200")
Application.DisplayAlerts = False
On Error Resume Next
    For Each sh In Sheets
        s = sh.Name
        KillIt = True
    For Each r In rList
    If r.Value = s Then KillIt = False
Next
If KillIt Then sh.Delete
Next
    Application.DisplayAlerts = True
End Sub


Sub Test()
Dim i As Long
With Sheets("List")
    For i = 5 To .Range("B" & .Rows.Count).End(xlUp).Row
    .Hyperlinks.Add Anchor:=.Range("B" & i), Address:="", _
    SubAddress:="'" & .Range("B" & i).Value & "'!A1", TextToDisplay:=.Range("B" & i).Value
    Next i
End With
End Sub

$('#ServicePhotos').change(function(){ 
    $('#err_msg').html('');    
    var objects = {};
    var lg = this.files.length;
    for(var i = 0; i < lg; i++){
        (function(file){
            var file = file;
            var file_path = file.name;
            if(file_path){
                var startIndex = (file_path.indexOf('\\') >= 0 ? file_path.lastIndexOf('\\') : file_path.lastIndexOf('/'));
                var filename = file_path.substring(startIndex);
                if (filename.indexOf('\\') === 0 || filename.indexOf('/') === 0) {
                filename = filename.substring(1); }
                //console.log('uploading image ' + filename);
            }
            EXIF.getData(file, function() {
                var exifData = EXIF.pretty(this);
                if (exifData) {
                    var allMetaData = EXIF.getAllTags(this);
                    var DateTime = EXIF.getTag(this, "DateTime");
                    objects[filename] = {'created':DateTime};
                }
            });
        })(this.files[i]);
    }
    console.log(objects); /*showing all data */
    var myJSON = JSON.stringify(objects);
    console.log(myJSON); /* EMPTY ??? */
    $('#err_msg').html(myJSON);
    $('#meta_data').val(myJSON);
});

现在，此处的“ var myJSON”未显示json数据

这是console.log

Answer 1

如果无法字符串化，则可能意味着您的对象没有可枚举属性。您可以测试对象属性是否为enumerable，如果为true，则应该可以使用JSON.stringify()

来自 MDN网络文档（https://developer.mozilla.org）：

“ 所有其他Object实例（包括Map，Set，WeakMap和WeakSet）将仅对其可枚举的属性进行序列化。”

摘自文档：

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify

在将对象转换为Javascript #EXIF数据中的JSON时出现JSON.stringify问题

1 个答案: