僅從JSON陣列中獲取第一個值。我應該怎么辦？-有解無憂

※請理解我英語不好，所以我使用翻譯來提問。※

您想要匯入并使用 JSON 陣列中的所有值。

但是，我在寫完代碼后完成了加載，但似乎只有第一個或最后一個值出來。添加陣列編號并嘗試了所有方法，但未收到任何值或發生錯誤。

在堆疊溢位中找到并使用了獲取 JSON 陣列中的值的代碼：Delphi parse JSON array or array

JSON 代碼與我的有點不同，但我對其進行了一些修改，它運行良好。但是，我問專家是因為只提出第一個或最后一個值是荒謬的。

//============JSON CODE===============
[
    {
        "VehicleWeight": "3.5?",
        "AlightArea": "?? ??? ??? ???",
        "Fee_Driver": "70000",
        "LoadArea": "?? ??? ???",
        "Commission": "0",
        "LiveTime": "2022-08-19 09:39:05",
        "AlightDate": "2022-08-19",
        "LoadDate": "2022-08-19",
        "GoodName": "",
        "ActionName": "??",
        "VehicleType": "??",
        "sk": "data#",
        "OrderCondition": "3",
        "Transport_ID": "B2682B5FC09C4CE38F2F14C84C4829D1",
        "pk": "B2682B5FC09C4CE38F2F14C84C4829D1#owner",
        "MultiLoading": "0",
        "Shipper_Name": "??????(?)"
    },
    {
        "VehicleWeight": "5??",
        "AlightArea": "?? ??? ???",
        "Fee_Driver": "130000",
        "LoadArea": "?? ??? ??? ???",
        "Commission": "0",
        "LiveTime": "2022-08-19 09:00:00",
        "AlightDate": "2022-08-19",
        "LoadDate": "2022-08-19",
        "GoodName": "??",
        "ActionName": "??",
        "VehicleType": "??",
        "sk": "data#",
        "OrderCondition": "3",
        "Transport_ID": "AB8D6C1ABA30497E95BD6FFF287E47A5",
        "pk": "AB8D6C1ABA30497E95BD6FFF287E47A5#owner",
        "MultiLoading": "0",
        "Shipper_Name": "??????(?)"
    },
    {
        "VehicleWeight": "2.5?",
        "AlightArea": "?? ??? ???",
        "Fee_Driver": "90000",
        "LoadArea": "?? ??? ???",
        "Commission": "0",
        "LiveTime": "2022-08-19 11:06:24",
        "AlightDate": "2022-08-19",
        "LoadDate": "2022-08-19",
        "GoodName": "",
        "ActionName": "??",
        "VehicleType": "??",
        "sk": "data#",
        "OrderCondition": "3",
        "Transport_ID": "F103B2FC1A8B42C9BCB350A8041BCEA4",
        "pk": "F103B2FC1A8B42C9BCB350A8041BCEA4#owner",
        "MultiLoading": "0",
        "Shipper_Name": "??????(?)"
    },
    {
        "VehicleWeight": "5?",
        "AlightArea": "?? ??? ???",
        "Fee_Driver": "120000",
        "LoadArea": "?? ??? ??? ???",
        "Commission": "0",
        "LiveTime": "2022-08-19 09:00:00",
        "AlightDate": "2022-08-19",
        "LoadDate": "2022-08-19",
        "GoodName": "",
        "ActionName": "??",
        "VehicleType": "???",
        "sk": "data#",
        "OrderCondition": "3",
        "Transport_ID": "C468AAC449B343CB8CB3349CD9FD46A7",
        "pk": "C468AAC449B343CB8CB3349CD9FD46A7#owner",
        "MultiLoading": "0",
        "Shipper_Name": "??????(?)"
    },
    {
        "VehicleWeight": "5?",
        "AlightArea": "?? ???",
        "Fee_Driver": "220000",
        "LoadArea": "?? ??? ???",
        "Commission": "0",
        "LiveTime": "2022-08-19 10:03:16",
        "AlightDate": "2022-08-19",
        "LoadDate": "2022-08-19",
        "GoodName": "",
        "ActionName": "??",
        "VehicleType": "??",
        "sk": "data#",
        "OrderCondition": "3",
        "Transport_ID": "A89FE76963374084933E89C3BD4CB57C",
        "pk": "A89FE76963374084933E89C3BD4CB57C#owner",
        "MultiLoading": "0",
        "Shipper_Name": "??????(?)"
    },
    {
        "VehicleWeight": "5?",
        "AlightArea": "?? ??? ???",
        "Fee_Driver": "120000",
        "LoadArea": "?? ??? ???",
        "Commission": "0",
        "LiveTime": "2022-08-19 09:46:20",
        "AlightDate": "2022-08-19",
        "LoadDate": "2022-08-19",
        "GoodName": "7.5??",
        "ActionName": "??",
        "VehicleType": "???",
        "sk": "data#",
        "OrderCondition": "3",
        "Transport_ID": "846A5E797D9E4A8097D816C83FE0034E",
        "pk": "846A5E797D9E4A8097D816C83FE0034E#owner",
        "MultiLoading": "0",
        "Shipper_Name": "??????(?)"
    },
    {
        "VehicleWeight": "5?",
        "AlightArea": "?? ??? ???",
        "Fee_Driver": "110000",
        "LoadArea": "?? ??? ???",
        "Commission": "0",
        "LiveTime": "2022-08-19 11:00:00",
        "AlightDate": "2022-08-19",
        "LoadDate": "2022-08-19",
        "GoodName": "",
        "ActionName": "??",
        "VehicleType": "??/???",
        "sk": "data#",
        "OrderCondition": "1",
        "Transport_ID": "780F2633C16542809FBB96ADADFFBA35",
        "pk": "780F2633C16542809FBB96ADADFFBA35#owner",
        "MultiLoading": "0",
        "Shipper_Name": "??????(?)"
    }
]

unit Unit1;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Vcl.ComCtrls, IdSSL , IdSSLOpenSSL, HTTPApp , IdURI,
  IdBaseComponent, IdComponent, IdTCPConnection, IdTCPClient, IdHTTP, System.JSON,
  Vcl.Grids, Data.DB, Vcl.DBGrids;

type
  TForm1 = class(TForm)
    DateTimePicker1: TDateTimePicker;
    Edit1: TEdit;
    Button1: TButton;
    IdHTTP1: TIdHTTP;
    StringGrid1: TStringGrid;
    editPK: TEdit;
    Memo1: TMemo;
    Button2: TButton;
    procedure Button1Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure StringGrid1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

{Automatic column size adjustment}
procedure AutoSizeGridColumn(Grid : TStringGrid; column : integer);
var
  i : integer;
  temp : integer;
  max : integer;
begin
  max := 0;
  for i := 0 to (Grid.RowCount-1) do
  begin
    // Among the width of each row in the specified column based on Grid Canvas
// The maximum value is determined by the width of the column
    temp := Grid.Canvas.TextWidth(grid.cells[column, i]);
    if temp > max then
      max := temp;
  end;
  Grid.ColWidths[column] := max   Grid.GridLineWidth   20;
end;
{End of autosize Column}
//*************************************************************

//==========================Get JSON array values=========================
function getData(JsonString: String; User: String; Field: String): String;
var
  JSonValue: TJSonValue;
  JsonArray: TJSONArray;
  ArrayElement: TJSonValue;
  FoundValue: TJSonValue;
begin
  Result :='';

  // create TJSonObject from string
  JsonValue := TJSonObject.ParseJSONValue(JsonString);

  // get the array
  JsonArray := JsonValue as TJSONArray;

  // iterate the array
  for ArrayElement in JsonArray do begin
    FoundValue := ArrayElement.FindValue(User);
    if FoundValue <> nil then begin
      Result := ArrayElement.GetValue<string>(Field);
      break;
    end;
  end;
end;
//==========================End of getting JSON array values=========================

procedure TForm1.Button1Click(Sender: TObject);
var
  idhttps: TIdHTTP;
  sslIOHandler : TIdSSLIOHandlerSocketOpenSSL;
  lStream : TStringStream;
  JSONValue : TJSONValue;
  JSONArray : TJSONArray;
  JSONObject, JSONdata: TJSONObject;
  JSONCount: integer;
  RESULT : String;
  ArrayElement: TJSonValue;
  FoundValue: TJSonValue;
  i : integer;
begin
  Try
    Result := '';
    idhttps := TIdHTTP.Create();
    lStream := TStringStream.Create(nil);
    sslIOHandler := TIdSSLIOHandlerSocketOpenSSL.Create(nil);
    Try
      sslIOHandler.SSLOptions.Method := sslvSSLv23;
      sslIOHandler.SSLOptions.Mode := sslmClient;

      idhttps.IOHandler := sslIOHandler;

      // idhttps.Request.CustomHeaders.Add(pAuthorization);
      idhttps.HandleRedirects :=False;
      idhttps.Request.Method := 'GET';
      idhttps.Response.ContentType := 'application/json; charset=utf-8';
      idhttps.ConnectTimeout := 10000;
      idhttps.ReadTimeout := 10000;

      lStream.Position := 0;
      idhttps.Get('insert JSON URL', lStream, []);
    Finally
      Result := TEncoding.UTF8.GetString(lStream.Bytes,0, lStream.Size);
      JsonArray := TJSONObject.ParseJSONValue(Result) as TJSONArray;
      JSONCount := JsonArray.Count;
      StringGrid1.RowCount := JSONCount 1;

      for i := 0 to (jsonCount)-1 do
        for ArrayElement in JsonArray do begin
          StringGrid1.Cells[00,i 1] := getdata(Result, '', 'ActionName');//Status
          StringGrid1.Cells[02,i 1] := getdata(Result, '', 'Shipper_Name');//Company Name
          StringGrid1.Cells[03,i 1] := getdata(Result, '', 'LoadDate');//Different day
          StringGrid1.Cells[04,i 1] := getdata(Result, '', 'LoadArea');//to take over
          StringGrid1.Cells[05,i 1] := getdata(Result, '', 'AlightArea');//Downloading
          StringGrid1.Cells[06,i 1] := getdata(Result, '', 'AlightDate');//Departure Day
          StringGrid1.Cells[07,i 1] := getdata(Result, '', 'VehicleType');//model
          StringGrid1.Cells[08,i 1] := getdata(Result, '', 'VehicleWeight');// tonnage
          StringGrid1.Cells[09,i 1] := getdata(Result, '', 'GoodName');//Cargo information
          StringGrid1.Cells[10,i 1] := getdata(Result, '', 'Fee_Driver');//vehicle freight
          StringGrid1.Cells[11,i 1] := getdata(Result, '', 'Commission');//commission
          StringGrid1.Cells[12,i 1] := getdata(Result, '', 'sk');//pk
          StringGrid1.Cells[13,i 1] := getdata(Result, '', 'pk');//sk

          {if StringGrid1.Cells[13,i 1] = '300016244318#9977' then
          begin
            StringGrid1.Cells[01,i 1] := 'O'//????
          end
          else
          begin
            StringGrid1.Cells[01,i 1] := '';//????
          end;   }
        end;

      {StringGrid1 Auto-Size Cell}
      for i := 0 to StringGrid1.ColCount-1 do
      begin
        AutoSizeGridColumn(StringGrid1, i);
      end;
      {StringGrid1 Auto-Size Cell END}

      FreeAndNil(lStream);
      FreeAndNil(idhttps);
      FreeAndNil(sslIOHandler);

    End;
  except
    on E: EIdHTTPProtocolException do
    begin
      Result := e.ErrorMessage;
      FreeAndNil(idhttps);
      FreeAndNil(sslIOHandler);
    end;

  End;
end;

end.

uj5u.com熱心網友回復：

我在這段代碼中看到了很多問題。

在Button1Click()中，外部for回圈是不必要的，應該洗掉。在這兩個for回圈之間，您正在不必要地一遍又一遍地重新回圈通過同一個陣列。內for..in回圈就足夠了。

getValue()此外，將原始 JSON 作為字串是沒有意義的，因為Button1Click()已經將其決議出來，只是getValue()一次又一次地重新決議它。大量浪費的開銷。您應該傳遞現有的TJSONArray甚至是ArrayElementto getValue()（或者更好的是，完全消除getValue()并將其邏輯直接移入Button1Click，特別是因為您的呼叫FindValue(User)沒有意義，因為User總是空白）。

此外，getData()并且Button1Click()都泄漏了回傳的TJSONValue物件ParseJSONValue()。

此外，您應該使用TIdHTTP.Get()回傳 astring而不是填充 a的多載TStream。

此外，您try..finally的 s 需要進行一些清理，您沒有充分保護所有物件免受錯誤的影響。

綜上所述，嘗試更多類似的東西：

unit Unit1;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Vcl.ComCtrls, IdSSL , IdSSLOpenSSL, HTTPApp , IdURI,
  IdBaseComponent, IdComponent, IdTCPConnection, IdTCPClient, IdHTTP, System.JSON,
  Vcl.Grids, Data.DB, Vcl.DBGrids;

type
  TForm1 = class(TForm)
    DateTimePicker1: TDateTimePicker;
    Edit1: TEdit;
    Button1: TButton;
    IdHTTP1: TIdHTTP;
    StringGrid1: TStringGrid;
    editPK: TEdit;
    Memo1: TMemo;
    Button2: TButton;
    procedure Button1Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure StringGrid1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

{Automatic column size adjustment}
procedure AutoSizeGridColumn(Grid : TStringGrid; Column : integer);
var
  i : integer;
  temp : integer;
  max : integer;
begin
  max := 0;
  for i := 0 to Grid.RowCount-1 do
  begin
    // Among the width of each row in the specified column based on Grid Canvas
    // The maximum value is determined by the width of the column
    temp := Grid.Canvas.TextWidth(Grid.Cells[Column, i]);
    if temp > max then
      max := temp;
  end;
  Grid.ColWidths[Column] := max   Grid.GridLineWidth   20;
end;
{End of autosize Column}
//*************************************************************

procedure TForm1.Button1Click(Sender: TObject);
var
  idhttps: TIdHTTP;
  sslIOHandler : TIdSSLIOHandlerSocketOpenSSL;
  JSONValue : TJSONValue;
  JSONArray : TJSONArray;
  ArrayElement: TJSONValue;
  i : integer;
begin
  idhttps := TIdHTTP.Create;
  try
    sslIOHandler := TIdSSLIOHandlerSocketOpenSSL.Create(idhttps);
    sslIOHandler.SSLOptions.Mode := sslmClient;
    sslIOHandler.SSLOptions.Method := sslvSSLv23;
    idhttps.IOHandler := sslIOHandler;

    // idhttps.Request.CustomHeaders.Add(pAuthorization);
    idhttps.HandleRedirects := False;
    idhttps.ConnectTimeout := 10000;
    idhttps.ReadTimeout := 10000;

    idhttps.HTTPOptions := idhttps.HTTPOptions   [hoNoProtocolErrorException, hoWantProtocolErrorContent];

    Result := idhttps.Get('insert JSON URL');
  finally
    idhttps.Free;
  end;

  JSONValue := TJSONObject.ParseJSONValue(Result);
  try
    JsonArray := JSONValue as TJSONArray;
    StringGrid1.RowCount := JsonArray.Count   1;

    i := 1;
    for ArrayElement in JsonArray do
    begin
      StringGrid1.Cells[00,i] := ArrayElement.GetValue<string>('ActionName','');//Status
      StringGrid1.Cells[02,i] := ArrayElement.GetValue<string>('Shipper_Name','');//Company Name
      StringGrid1.Cells[03,i] := ArrayElement.GetValue<string>('LoadDate','');//Different day
      StringGrid1.Cells[04,i] := ArrayElement.GetValue<string>('LoadArea','');//to take over
      StringGrid1.Cells[05,i] := ArrayElement.GetValue<string>('AlightArea','');//Downloading
      StringGrid1.Cells[06,i] := ArrayElement.GetValue<string>('AlightDate','');//Departure Day
      StringGrid1.Cells[07,i] := ArrayElement.GetValue<string>('VehicleType','');//model
      StringGrid1.Cells[08,i] := ArrayElement.GetValue<string>('VehicleWeight','');// tonnage
      StringGrid1.Cells[09,i] := ArrayElement.GetValue<string>('GoodName','');//Cargo information
      StringGrid1.Cells[10,i] := ArrayElement.GetValue<string>('Fee_Driver','');//vehicle freight
      StringGrid1.Cells[11,i] := ArrayElement.GetValue<string>('Commission','');//commission
      StringGrid1.Cells[12,i] := ArrayElement.GetValue<string>('sk','');//pk
      StringGrid1.Cells[13,i] := ArrayElement.GetValue<string>('pk','');//sk

      {if StringGrid1.Cells[13,i] = '300016244318#9977' then
      begin
        StringGrid1.Cells[01,i] := 'O'//????
      end else begin
        StringGrid1.Cells[01,i] := '';//????
      end;}
      
      Inc(i);
    end;
  finally
    JSONValue.Free;
  end;

  {StringGrid1 Auto-Size Cell}
  for i := 0 to StringGrid1.ColCount-1 do
  begin
    AutoSizeGridColumn(StringGrid1, i);
  end;
  {StringGrid1 Auto-Size Cell END}
end;

end.

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標籤：json 德尔福

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