分类：
2008-10-13 16:38:14
按数据库记录构建树控件
作者:
代码运行效果图如下:
简介:
将树中的每一个项目作为数据库中的一条记录(ACCESS2000),将程序启动时,对数据库进行读操作;创建树的各个项目时,是对数据库进行读操作,每次的读取,都是在可是查寻符合条件的记录,并将其一一添加到树中!
实现方法:
准备:
使用ACCESS2000,创建一个数据库,名字为City.mdb(我们将制作一个关于省与市的树,特别适合通讯录);
在数据库中创建一表,表名为TreeItem,字段内容与类型如下图:
 |
ID: 索引号码(可有,可无) Name: 项目名称(必须) ParentItem: 父项名称(必须) SecNum: 电话区号(可有,可无) |
输入一些原始数据.数据库已经准备好,那我们就进行实地的编程阶段.
程序实现:
创建一个基于对话框的工程---TreeData
一.ADO的引入和初始化
//--------------------------------------------
#import "c:\program files\common files\system\ado\msado15.dll" no_namespace rename("EOF","adoEOF")
//--------------------------------------------
2.在TreeData.h中声明两个私有变量:
public: _ConnectionPtr m_pTreeConn;//连接创建 private: CString TreeConnString;//连接字符串3.在CTreeDataApp的构造函数CTreeDataApp中添加如下代码:
//-------------------------------------------
m_TreeConnString=_T("Provider=Microsoft.Jet.OLEDB.4.0;")
_T("Data Source=DataBase\\City.mdb;");
//-------------------------------------------
4.在CTreeDataApp的初始化函数中添加如下代码:
//-------COM初始化--------------------------------
AfxOleInit();
/******************连接通讯录数据库********************/
HRESULT hRes;
try
{
hRes=m_pTreeConn.CreateInstance(_T("ADODB.Connection"));
m_pTreeConn->ConnectionTimeout = 8;
//连接ACCESS2000
hRes=m_pTreeConn->Open(_bstr_t((LPCTSTR) m_strTelDataSource),
_T(""),_T(""),adModeUnknown);
}
catch(_com_error e)///捕捉异常
{
CString errormessage;
errormessage.Format(_T("连接TelBook.mdb数据库失败!\r\n错误信息:%s"),e.ErrorMessage());
AfxMessageBox(errormessage);///显示错误信息
return FALSE;
}
二.Recordset的创建://------------------------------------------ private: HRESULT hRes; _RecordsetPtr m_TreeRecordset; //用于创建一个查询记录集 //------------------------------------------ public: CImageList m_TreeBootImage; //Tree的图标2. (1).在对话框窗口中添加一个TreeCtrl控件,一个ComboExe控件; TreeCtrl的风格设置如下图;
void CBusinessView::TreeAddTree(bool Ta)
{
//--------------Tree控件操作变量------------------------
TVINSERTSTRUCT tvInsert;
HTREEITEM hParent;
//------------------------------------------------
tvInsert.hParent = NULL;
tvInsert.hInsertAfter = NULL;
tvInsert.item.mask = TVIF_TEXT;
//-----------------创建图象标签----------------------------
m_TreeBootImage.Create ( IDB_TreeBootImage,20,1,ILC_COLOR8);
m_ctrlTree.SetImageList ( &m_TreeBootImage,TVSIL_NORMAL );
m_ctrlTree.SetTextColor (RGB(7,145,13));
//--------添加根目录----------------------------------------
tvInsert.item.pszText = _T("中国");
hParent = m_ctrlTree.InsertItem(&tvInsert);
//---------------添加子目录-------------------------------
TreeAddSubTree("中国","1",hParent);
//---------------------展开Tree目录------------------
m_ctrlTree.Expand(hParent,TVE_EXPAND);
}
4.添加一个COM变量到CString变量的转换函数:
//-----------------实现了VARIANT类型的值转换成CString类型--------------
CString CBusinessView::VariantToCString(VARIANT var)
{
CString strValue;
_variant_t var_t;
_bstr_t bst_t;
time_t cur_time;
CTime time_value;
COleCurrency var_currency;
switch(var.vt)
{
case VT_EMPTY:strValue=_T("");break;
case VT_UI1:strValue.Format ("%d",var.bVal);break;
case VT_I2:strValue.Format ("%d",var.iVal );break;
case VT_I4:strValue.Format ("%d",var.lVal);break;
case VT_R4:strValue.Format ("%f",var.fltVal);break;
case VT_R8:strValue.Format ("%f",var.dblVal);break;
case VT_CY:
var_currency=var;
strValue=var_currency.Format(0);
break;
case VT_BSTR:
var_t=var;
bst_t=var_t;
strValue.Format ("%s",(const char*)bst_t);
break;
case VT_NULL: strValue=_T(""); break;
case VT_DATE:
cur_time=var.date;
time_value=cur_time;
strValue=time_value.Format("%A,%B%d,%Y");
break;
case VT_BOOL: strValue.Format ("%d",var.boolVal ); break;
default: strValue=_T(""); break;
}
return strValue;
}
5.同样的方法添加另外一个成员函数TreeAddSubTree(CString
ParTree,CString strChildTree,HTREEITEM hPartItem): if (strChildTree!="0")
{
//----------------使用到的变量进行定义----------
_RecordsetPtr m_pTreeRecordset; //用于创建一个查询记录集
_variant_t vChild;
//--------------Tree控件操作变量------------------------
HTREEITEM hCurrent;
//----------------------------------------------
CString strSQL,strCurItem;
//-----------------------------------------------
strSQL="SELECT * FROM TreeItem where ParentItem like ''%" ;
strSQL=strSQL+ParTree+"%''";
try
{
HRESULT hTRes;
hTRes = m_pTreeRecordset.CreateInstance(_T("ADODB.Recordset"));
if (SUCCEEDED(hTRes))
{
//----------------------------------------------------
hTRes = m_pTreeRecordset->Open((LPTSTR)strSQL.GetBuffer(130),
_variant_t((IDispatch *)(((CBusinessApp*)AfxGetApp())->m_pTreeConnection),true),
adOpenDynamic,adLockPessimistic,adCmdText);
if(SUCCEEDED(hTRes))
{
TRACE(_T("连接成功!\n"));
//------------------------------------------
m_pTreeRecordset->MoveFirst();
if (!(m_pTreeRecordset->adoEOF))
{
while(!m_pTreeRecordset->adoEOF)
{
hCurrent = m_ctrlTree.InsertItem((LPCTSTR)(_bstr_t) (m_pTreeRecordset->GetCollect("Name")), hPartItem, NULL);
//---------------将内容添加到City的Combo控件中------------------
m_ctrlComboCity.AddString(VariantToCString(m_pTreeRecordset->GetCollect("Name")));
if (TreeSumRecordCount(VariantToCString (m_pTreeRecordset->GetCollect("Name")))>0)
{
TreeAddSubTree(VariantToCString(m_pTreeRecordset->GetCollect("Name")),
(VariantToCString(m_pTreeRecordset->GetCollect("Name"))),
hCurrent);
}
if (!(m_pTreeRecordset->adoEOF))
{
m_pTreeRecordset->MoveNext();
}
}
}
//---------------------------------------
}
}
}
catch(_com_error e)///捕捉异常
{
CString errormessage;
MessageBox("创建City记录集失败!",ParTree+strChildTree);
}
}
6.添加一个求当前项子项串的成员函数ReturnTreeChilds(CString
strCurItem)://----------------提取当前所选择项的子项文本所组成的字符串------------------------
CString CTreeDataDlg::ReturnTreeChilds(CString strCurItem)
{
CString strTreeChildren;//记录子项文本所组成的字符串
if (TreeSumRecordCount(strCurItem) > 0)
{
//--------------------进入递归运算---------------------
_RecordsetPtr m_pTreeRecordset; //用于创建一个查询记录集
_variant_t vCur;
CString strSQL;
//-----------------------------------------------
strSQL="SELECT * FROM TreeItem where ParentItem like ''%" ;
strSQL=strSQL+strCurItem+"%''";
try
{
HRESULT hTRes;
hTRes = m_pTreeRecordset.CreateInstance(_T("ADODB.Recordset"));
if (SUCCEEDED(hTRes))
{
//----------------------------------------------------
hTRes = m_pTreeRecordset->Open((LPTSTR)strSQL.GetBuffer(130),
_variant_t((IDispatch *)(((CTreeDataApp*)AfxGetApp())->m_pTreeConn),true),
adOpenDynamic,adLockPessimistic,adCmdText);
if(SUCCEEDED(hTRes))
{
TRACE(_T("连接成功!\n"));
//------------------------------------------
m_pTreeRecordset->MoveFirst();
vCur=(m_pTreeRecordset->GetCollect("Name"));
if (TreeSumRecordCount(VariantToCString(vCur))>=0)
{
while(!m_pTreeRecordset->adoEOF)
{
vCur=(m_pTreeRecordset->GetCollect("Name"));
strTreeChildren+=(",''"+VariantToCString(vCur)+"''");
if (TreeSumRecordCount(VariantToCString(vCur))!=0)
{
strTreeChildren+=ReturnTreeChilds(VariantToCString(vCur));
}
if (!(m_pTreeRecordset->adoEOF))
{
m_pTreeRecordset->MoveNext();
}
}
}
//---------------------------------------
}
}
}
catch(_com_error e)///捕捉异常
{
CString errormessage;
AfxMessageBox("创建ChildTree记录集失败!"+strCurItem);
}
}
return strTreeChildren;
}
7.处理TreeCtrl控件的点击(OnClick)和改变选择项(SelchangedTree)事件:
void CTreeDataDlg::OnSelchangedTree1(NMHDR* pNMHDR, LRESULT* pResult)
{
NM_TREEVIEW* pNMTreeView = (NM_TREEVIEW*)pNMHDR;
//--------------------------------------------------------
hTreeCurrent=m_ctrlTree.GetSelectedItem ();
hTreeParent=m_ctrlTree.GetParentItem(m_ctrlTree.GetSelectedItem ());
//-------------------树型控件的图标更改---------
m_ctrlTree.SetItemImage(hTreeCurrent,1,true );
//----------------------------------------------
TreeCurrent="''"+m_ctrlTree.GetItemText(hTreeCurrent)+"''";
TreeParent=m_ctrlTree.GetItemText (hTreeParent);
//---------------------处理ListTree中的相应显示内容--------------
//-------------提取树中当前项及其子项的内容------
hTreeCurrent=m_ctrlTree.GetSelectedItem ();
m_strEdit=TreeCurrent+ReturnTreeChilds(m_ctrlTree.GetItemText(hTreeCurrent));
UpdateData(false);//子项内容显示到Edit控件中
//---------------------------------------------------
*pResult = 0;
}
void CTreeDataDlg::OnClickTree1(NMHDR* pNMHDR, LRESULT* pResult)
{
//-------------------树型控件的图标还原---------
m_ctrlTree.SetItemImage(hTreeCurrent,0,true );
//----------------------------------------------
*pResult = 0;
}
三.在BOOL
CTreeDataDlg::OnInitDialog()中添加以下代码:
TreeAddTree();
总结:
这个程序主要是在数据库中进行操作,主干是两个递归成员函数;对于递归,让你自己来理解吧!
写的不错收藏了！ ( ddlddy 发表于 2008-8-21 10:23:00) 怎么后面的没有跟进了啊 ( haifengcumt 发表于 2008-1-6 22:50:00) 我在调试过程中，发现一个问题。希望对感兴趣的人有一点帮助。 要是使用ODBC应该怎么实现 ( jichunxiang 发表于 2003-8-26 17:10:00) 谢谢作者，我刚好要用的这个，太感激了 ( angle_88 发表于 2003-7-8 10:01:00) 如果数据库的表多了一个兄弟节点,那递归算法该怎么写呢? ( sunrenliang 发表于 2002-12-28 13:59:00) 编译第一次就出错，多写点，把LISTVIEW32也关联进来 ( hww02 发表于 2002-12-12 14:24:00) 文章不错，写得很仔细。图文并茂.哪天没事我也写一个。 ( liuc_xxx 发表于 2002-12-5 15:40:00) 对我现在的工作帮助很大,谢谢!!! 对我很实用，但我想问一下：如果有与之关联的列表框listctrl怎么办，向资源管理器那样 ( neter 发表于 2002-12-3 8:40:00)