(04)Lazarus上连接并显示SQlLite3数据库 - 涂磊

Lazarus_SQLite完美框架4源文件下载,一定要放在D:\lazarus\project2目录下,不要问为什么.

链接：https://pan.baidu.com/s/14nTKCCoA0lVB2jYvXMADgQ
提取码：evyp

相关文件打包下载链接：https://pan.baidu.com/s/1gouuR8IfAHnwvNQ5YvZvSg
提取码：8i2s

01]去官网https://www.sqlite.org/download.html下载对应的SQlite3.dll

02]设置SQLQuery1.SQL 原理图：

021]添加一行数据

022]Lazarus中DBGrid (MEMO)显示明细

023]Lazarus DBGrid隔行颜色交替

024]即点即输，回车提交

025]修改默认列的显示列名，并可设置字体颜色，居中

026]固定行固定列的颜色FixedColor改变

03]常见问题：

01]去官网https://www.sqlite.org/download.html 下载对应的SQlite3.dll

32位Lazarus下载sqlite-dll-win-x86-3440200.zip

64位Lazarus下载sqlite-dll-win-x64-3440200.zip

下载后，将SQlite3.dll放在工程目录下

拖一个SQLDBLibraryLoader1放在界面上，设置它的ConnectionType和LibraryName

最后，设置它的Enabled为True后,一定要绝对路径

再拖一个SQLConnector1，一定要绝对路径

设置SQLDBLibraryLoader1的Enabled为False

02]设置SQLQuery1.SQL

select * from userinfo

原理图：

021]添加一行数据

procedure TForm1.Button1Click(Sender: TObject);
begin
  SQLQuery1.Active:=false;
  SQLite3Connection1.ExecuteDirect('INSERT INTO  userinfo VALUES (8, ''asdf'', ''asdfasdf'')');
 // SQLTransaction1.Commit;
  SQLQuery1.Active:=true;
end;

022]Lazarus中DBGrid 1(MEMO)显示明细

方法1：设置DBGrid1的Options的dgDisplayMemoTest为True即可

方法2： https://forum.lazarus.freepascal.org/index.php/topic,19339.msg110012.html#msg110012

procedure TForm1.DBGrid1PrepareCanvas(sender: TObject; DataCol: Integer;
  Column: TColumn; AState: TGridDrawState);
var
  MyTextStyle: TTextStyle;
begin
  //选择要显示文本的列号
  if (DataCol = 1) or (DataCol = 2)then
  begin
    // The next is not neccesary but you can use it to adjust your text appearance.
    // you can change colors, font, size, as well other parameters.
    MyTextStyle := TDBGrid(Sender).Canvas.TextStyle;
    MyTextStyle.SingleLine := False;
    MyTextStyle.Wordbreak  := False;
    TDBGrid(Sender).Canvas.TextStyle := MyTextStyle;

    // Here how to show any text:
    // just assign an event procedure to OnGetText of the Field.
    Column.Field.OnGetText := @Form1.DBGridOnGetText;
  end;
end;

再手动添加Form1.DBGridOnGetText过程

procedure TForm1.DBGridOnGetText(Sender: TField; var aText: string;
  DisplayText: Boolean);
begin
   if (DisplayText) then   Text := Sender.AsString;
end;

023]Lazarus DBGrid隔行颜色交替,很简单，只需设置AlternateColor指定颜色就可以。

024]即点即输，回车提交

0241]DBGrid1的dgEditing属性一定要设为True,

0242]DBGrid1接收回车后的事件

procedure TForm1.DBGrid1KeyUp(Sender: TObject; var Key: Word; Shift: TShiftState   );
begin
    If (Key = 13) and (SQLQuery1.State=dsEdit)   then      SQLQuery1.Post;
end;

0243]SQLQuery1的3个属性必须设为True;