Try..Except..End 例外狀況處理

Try

  ...

  ...

Except

  ...

End;

Exception

Try

  ...

  ...

Except

   on E:Exception do

  begin

    MessageBox(Handle, PWideChar(E.Message), PWideChar(E.Class), MB_ICONError);

  end

End;

Delphi DataSet和JSON互轉函式

 一、DataSet轉JSON

//1）資料集轉換為JSON字串：
//需USES System.JSON;

function DataSetToJson(ADataset: TDataSet): string;

var

  LRecord: string;

  LField: TField;

  i: integer;

begin

  Result := '';

  if (not ADataset.Active) or (ADataset.IsEmpty) then

    Exit;

  Result := '[';

  ADataset.DisableControls;

  ADataset.First;

  while not ADataset.Eof do

  begin

    for i := 0 to ADataset.FieldCount - 1 do

    begin

      LField := ADataset.Fields[i];

      if LRecord = '' then

        LRecord := '{"' + LField.FieldName + '":"' + LField.Text + '"'

      else

        LRecord := LRecord + ',"' + LField.FieldName + '":"' + LField.Text + '"';

      if i = ADataset.FieldCount - 1 then

      begin

        LRecord := LRecord + '}';

        if Result = '[' then

          Result := Result + LRecord

        else

          Result := Result + ',' + LRecord;

        LRecord := '';

      end;

    end;

    ADataset.Next;

  end;

  ADataset.EnableControls;

  Result := Result + ']';

end;

二、JSON轉DataSet

//2）JSON字串轉換為資料集：

procedure JsonToDataSet(AJson: string; ADataset: TDataSet);

var

  jDataSet: TJSONArray;

  jRecord: TJSONObject;

  i, j: Integer;

begin

  if (AJson = '') or (ADataset = nil) or (not ADataset.Active) then

    Exit;

  jDataSet := TJSONArray.Create;

  jDataSet := TJSONObject.ParseJSONValue(AJson, True) as TJSONArray;

  while not ADataset.Eof do

    ADataset.Delete;

  for i := 0 to jDataSet.Size - 1 do

  begin

    ADataset.Append;

    jRecord := jDataSet.Get(i) as TJSONObject;

    for j := 0 to ADataset.FieldCount - 1 do

    begin

      if ADataset.Fields[j].ReadOnly then

        Continue;

      ADataset.Fields[j].AsString := jRecord.GetValue(ADataset.Fields[j].FieldName).Value;

    end;

    ADataset.Post;

  end;

end;

轉貼至: https://www.itread01.com/content/1548927014.html，(因應語法及版本做適當的修正)

Json To ClientDataset

procedure JsonToClientDataset(AJson:String; AClientDataset:TClientDataset);

var

  jDataSet: TJSONArray;

  jRecord: TJSONObject;

  i, j: Integer;

  procedure CreateClientDataset;

  var k, iFieldCount:Integer;

    sFieldName:String;

  begin

    AClientDataset.Close;

    AClientDataset.Fields.Clear;

    AClientDataset.FieldDefs.Clear;

    jRecord := jDataSet.Get(0) as TJSONObject;

    iFieldCount := jRecord.Count; //欄位數

    for k := 0 to iFieldCount-1 do

    begin

      sFieldName := Trim(jRecord.Pairs[k].JsonString.Value);

      AClientDataset.FieldDefs.Add(sFieldName, ftString, 2000);

    end;

    AClientDataset.CreateDataSet;

  end;

begin

  if (AJson = '') or (AClientDataset = nil) then

    Exit;

  jDataSet := TJSONArray.Create;

  jDataSet := TJSONObject.ParseJSONValue(AJson, True) as TJSONArray;

  //

  CreateClientDataset;

  //

  for i := 0 to jDataSet.Size - 1 do

  begin

    AClientDataset.Append;

    jRecord := jDataSet.Get(i) as TJSONObject;

    for j := 0 to AClientDataset.FieldCount - 1 do

    begin

      AClientDataset.Fields[j].AsString := jRecord.GetValue(AClientDataset.Fields[j].FieldName).Value;

      jDataSet.Count;

    end;

    AClientDataset.Post;

  end;

end;

截取 ADO 錯誤訊息

 procedure ADOConnection1ExecuteComplete(Connection: TADOConnection; RecordsAffected: Integer;
  const Error: Error; var EventStatus: TEventStatus; const Command: _Command; const Recordset: _Recordset);
begin
  //ADO 錯誤訊息
  if EventStatus=esErrorsOccured then
  begin
    ShowMessage(Error.Description);
  end;
end;

組件資源引用

uses  AdoConEd;

if  AdoConEd.EditConnectionString(AdoConnection) then  ...

Path:
    C:\Program Files (x86)\Embarcadero\Studio\17.0\source\Property Editors

uses SQLEdit;