如何解决 B4A 中的“对象转换为字符串”错误

Question

Sub Process_Globals
'These global variables will be declared once when the application starts.
'These variables can be accessed from all modules.
Type DBResult (Tag As Object, **Columns As Map**, Rows As List)
Type DBCommand (Name As String, Parameters() As Object)
Private const rdcLink As String = "http://192.168.8.100:17178/rdc"
End Sub

This is the methods for process globals. Here columns As Map is initialized. However the line bolded in the below code gives an error as, "Object converted to String. This is probably a programming mistake. (warning #7)"

Sub GetRecord
Dim req As DBRequestManager = CreateRequest
Dim cmd As DBCommand = CreateCommand("selectAllNames", Null)
Wait For (req.ExecuteQuery(cmd, 0, Null)) JobDone(j As HttpJob)
If j.Success Then
    req.HandleJobAsync(j, "req")
    Wait For (req) req_Result(res As DBResult)
    'work with result
    'req.PrintTable(res)
    ***Log(res.Columns)***
    ListViewListTable.Clear
    For Each row() As Object In res.Rows
        Dim oBitMap As Bitmap
        Dim buffer() As Byte
        buffer = row(res.Columns.Get("gambar"))
        oBitMap = req.BytesToImage(buffer)
        ListViewListTable.AddTwoLinesAndBitmap(row(1), "See more...", oBitMap)
    Next
Else
    Log("ERROR: " & j.ErrorMessage)
End If
j.Release
End Sub

So what should I do to remove the error?

Answer 1

If columns is a map? (which it looks to be?).

Then to display the columns you can use this:

For Each MyKey As String in res.Columns.Keys
   log("Key name = " & MyKey)
   log("Key value = " & res.Columns.Get(MyKey))
Next