[SOLVED] Copy JSON string to a grid
lazarus / 38-Networking and Web Programming

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JD · 2015-10-25 19:19

Hi there everyone,

I have a problem that I've been wrestling with for a few days.

I'm trying to convert a JSON array into rows in a grid. I'm using the
TKGrid for this purpose.

Here is the JSON array:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i [   
{"NAME":"Patricia","SEX":"Female","COUNTRY":"Wales; "},   
{"NAME":"Pauline","SEX":"Female","COUNTRY":"Scotland; "},   
{"NAME":"Quinterie","SEX":"Female","COUNTRY":"France; "},   
{"NAME":"Salome","SEX":"Female","COUNTRY":"Israel; "},   
{"NAME":"Sandra","SEX":"Female","COUNTRY":"Wales; "},   
{"NAME":"Sigourney","SEX":"Female","COUNTRY":"England; "},   
{"NAME":"Silvia","SEX":"Female","COUNTRY":"Scotland; "},   
{"NAME":"Sonia","SEX":"Female","COUNTRY":"Italy; "},   
{"NAME":"Veronica","SEX":"Female","COUNTRY":"Ireland; "},   
{"NAME":"Viviane","SEX":"Female","COUNTRY":"France; "}] 
The code that copies the array into the grid is as follows:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TfrmQuery.FillGrid(AGrid: TKGrid; AString: string);var  fixedCols  :
integer;  fixedRows  : integer;  ARow,ACol  : integer;  intGridRow,
intGridCol : integer;  intLastUsedRow, intNumberOfRows,
intNumberOfColumns, intNumberOfSQLQueryRows: integer;  //  jsParser:
TJSONParser;  jsData: TJSONData;  //jsRow: TJSONEnum;begin  // 
fixedCols := AGrid.FixedCols;  fixedRows := AGrid.FixedRows; 
intLastUsedRow := AGrid.RowCount;  // get the old row & column count 
intNumberOfRows := AGrid.RowCount - fixedRows;  intNumberOfColumns :=
AGrid.ColCount - fixedCols;  //  jsParser  :=
TJSONParser.Create(AString);  //  try    // Parse the JSON data   
jsData := jsParser.Parse;    //    if jsData <> nil then begin      //
get the number of rows returned by the query in the JSON data object 
   intNumberOfSQLQueryRows := jsData.Count;      //     
AGrid.RowCount := AGrid.RowCount + intNumberOfSQLQueryRows;       //
append the json rows to the grid      for intGridRow := 0 to
intNumberOfSQLQueryRows - 1 do      begin        // Select the row
after the last used row        ARow := intGridRow + intLastUsedRow;  
    //        for intGridCol := 0 to intNumberOfColumns - 1 do       
begin          //          ACol := intGridCol + fixedCols;         
//          AGrid.Cells[ACol, ARow] :=
jsData.Items[intGridCol].AsString;  // ERROR HERE        end;    //
for intGridCol := 0 to intNumberOfColumns - 1 do      end;      // for
intGridRow := 0 to intNumberOfSQLQueryRows - 1 do    end;        // if
jsData <> nil then begin  finally    jsData.Clear;    jsParser.Free; 
end;end; 
On line 44, AGrid.Cells[ACol, ARow] :=
jsData.Items[intGridCol].AsString;, I get the EJSON exception cannot
convert data from object value.

I've looked at all the JSON examples as well as what is posted on this
forum but I still can't figure it out.

Thanks for your assistance.

JD

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Graeme · 2015-10-25 23:39

I haven't tried to compile or run your code, but from what I can see
by quickly reading through the code....

jsData.Items[intGridCol]

returns the JSON array element. You need to then process that array
element further by extracting the Name, Sex or Country data - based on
what you want to display in the grid cell.

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engkin · 2015-10-26 00:12

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i program
Project1; uses  fpjson, jsonparser; var  s:String; 
Parser:TJSONParser;  Arr:TJSONArray;  i: integer;begin  s :=  '['+   
 '{"NAME":"Patricia","SEX":"Female","COUNTRY":"Wales; "},'+     
'{"NAME":"Pauline","SEX":"Female","COUNTRY":"Scotland; "},'+     
'{"NAME":"Quinterie","SEX":"Female","COUNTRY":"France; "},'+     
'{"NAME":"Salome","SEX":"Female","COUNTRY":"Israel; "},'+     
'{"NAME":"Sandra","SEX":"Female","COUNTRY":"Wales; "},'+     
'{"NAME":"Sigourney","SEX":"Female","COUNTRY":"England; "},'+     
'{"NAME":"Silvia","SEX":"Female","COUNTRY":"Scotland; "},'+     
'{"NAME":"Sonia","SEX":"Female","COUNTRY":"Italy; "},'+     
'{"NAME":"Veronica","SEX":"Female","COUNTRY":"Ireland; "},'+     
'{"NAME":"Viviane","SEX":"Female","COUNTRY":"France; "}'+  ']';  
Parser:=TJSONParser.Create(s);  Arr := Parser.Parse as TJSONArray; 
WriteLn('Array of ',Arr.Count);  for i := 0 to Arr.Count - 1 do 
begin    SubObj := Arr.Objects[i];    WriteLn(i+1, ': ',
SubObj.Strings['NAME'], ', ', SubObj.Strings['SEX'], ', ',
SubObj.Strings['COUNTRY']);  end;  readln;  //...etcend. 
URL

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JD · 2015-10-26 20:18

Thanks a million for your replies Graeme & engkin.

@engkin Your example clarified things for me. It now works!

JD