一个很菜的问题，调试程序遇到的知道朋友来看看！在线等。。。UP 有分

Question

Could not convert variant of type(string) into Type(Boolean)我就是没能找到程序到底那出错了？有经验的朋友指点小弟一二。在线等

Answer 1

类型转换错了
不能把string变成boolean

Answer 2

你赋值错了，把String类型的变量赋给boolean类型的变量
或者把String类型的变量作判断的条件了。

Answer 3

调试的程序发现定义的三个变量有问题，但是能编译运行，我也没注意。有点奇怪，我明明是把String 和 Boolean 区别开来啊判断的也正确。真是怪事

Answer 4

字面这样显示，你再看看吧，string型变量不能赋给Boolean弄变量，设断点跟踪一下

Answer 5

字面这样显示，你再看看吧，string型变量不能赋给Boolean型变量，设断点跟踪一下

Answer 6

字面这样显示，你再看看吧，string型变量不能赋给Boolean型变量，设断点跟踪一下

Answer 7

全部代码：
unit Unit111;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, DB, ADODB, Grids, DBGrids, ExtCtrls, StdCtrls,JPEG, DBCtrls;type
  TXJK = class(TForm)
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    Label4: TLabel;
    Label5: TLabel;
    Label6: TLabel;
    Label7: TLabel;
    Edit1: TEdit;
    Edit2: TEdit;
    Edit3: TEdit;
    Edit4: TEdit;
    ComboBox1: TComboBox;
    ComboBox2: TComboBox;
    ComboBox3: TComboBox;
    Panel1: TPanel;
    DBGrid1: TDBGrid;
    ADOQuery1: TADOQuery;
    DataSource1: TDataSource;
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    Button4: TButton;
    ADOTable1: TADOTable;
    Image1: TImage;
    procedure Button4Click(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure DBGrid1DblClick(Sender: TObject);
    procedure Button3Click(Sender: TObject);
  private
    { Private declarations }
        strEmptyPhoto : string;
        bRecordChanged : Boolean;   //这两个变量有问题。  public
    { Public declarations }  end;var
  XJK: TXJK;implementation  Uses DataSet,Main,QuickPorts;{$R *.dfm}procedure TXJK.Button4Click(Sender: TObject);
begin
  ADOTable1.Filtered := False; //刷新数据。
end;procedure TXJK.Button1Click(Sender: TObject);
begin
  Close;
end;procedure TXJK.DBGrid1DblClick(Sender: TObject);
var
        NewBmp : TBitMap;
        NewMem : Tstream;
        //Tempstream : TMemorystream;
        //tempjpeg :TJpegImage;
begin
       if Not bRecordChanged and ADOQuery1.Active  then
        With ADOQuery1 do
        begin
        if eof then exit;
        Edit1.Text := FieldByName('XM').AsString;
        Combobox1.Text := FieldByName('XB').AsString;
        Edit2.Text := FieldByName('SFZH').AsString;
        Combobox2.Text := FieldByName('CXCX').AsString;
        Edit3.Text := FieldByName('C_DH').AsString;
        Combobox3.Text := FieldByName('ZJ1').AsString;
        Edit4.Text := FieldByName('ZHDZ').AsString;
        {try
        tempstream := TMemorystream.Create();
        TBlobField(adotable1.FieldByName('picture')).SaveToStream(tempstream);
        tempstream.Position := 0;
        tempjpeg := TJpegImage.Create;
        tempjpeg.LoadFromFile(tempstream);
        Image1.Picture.Bitmap.Assign(tempjpeg);
        finally
        tempjpeg.Free;
        tempstream.Free;}
        if Not(FieldValues['Photo']) and (Length(Trim(FieldValues['Photo']))>0) then
        begin
                NewBmp := TBitMap.Create;
                NewMem := CreateBlobStream(FieldByname('photo'),bmRead);
                NewBmp.LoadFromStream(NewMem);
                Image1.Picture.Assign(NewBmp);
                NewMem.Free;
                Image1.Free;
        end
        else
        Image1.Picture.LoadFromFile(strEmptyPhoto);
        end;
end;procedure TXJK.Button3Click(Sender: TObject);
var
    NewSQL : string;  //这个会有异常。
begin
        Try
        QuickRePort2 := TQuickRePort2.Create(Application);
        With QuickRePort2.ADOQuery1 do
        begin
                if Active then close;
                SQL.Clear;
                SQL.Add(NewSQL);
                Open;
                begin
                QuickReport2.PreviewModal;
                end;
        end;
        finally
        QuickRePort2.Free;
end;
end;end.

Answer 8

变量赋值问题,blooen 不能转为string