Delphi DataSet和JSON互转函数

一、DataSet转JSON
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//1）数据集转换为JSON字符串：
//需USES System.JSON;

function DataSetToJson(ADataset: TDataSet): string;
// [{“CityId”:”18”,”CityName”:”西安”},{“CityId”:”53”,”CityName”:”广州”}]
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转DataSet
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//2）JSON字符串转换为数据集：

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 := TJSONObject.Create.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
ADataset.Fields[j].Text := jRecord.GetValue(ADataset.Fields[j].FieldName).ToString;
ADataset.Post;
end;
end;