Question

怎样从数据库中读取数据生成树

Answer 1

private DataSet ds;
private SqlDataAdapter sqlDataAdapter1;
private int maxnodeid;

private void Form1_Load(object sender, System.EventArgs e)
{
string strconn=ConfigurationSettings.AppSettings["ConnStr"];
sqlConnection1 = new SqlConnection(strconn);
this.sqlConnection1.Open();
//填充DataSet
this.CreateDataSet();
//从数据库中读取数据，通过递归生成树。
InitTree(this.treeView1.Nodes,"0");

}

private void CreateDataSet()
{
this.sqlDataAdapter1=new SqlDataAdapter("select * from s_menu ",this.sqlConnection1);
this.ds=new DataSet();
this.sqlDataAdapter1.Fill(ds,"tree");
}
private void InitTree(TreeNodeCollection Nds,string parentId)
{
DataView dv=new DataView();
TreeNode tmpNd;
string intId;
dv.Table=ds.Tables["tree"];
dv.RowFilter="ParentId='" + parentId + "'" ;
foreach(DataRowView drv in dv)
{
tmpNd=new TreeNode();
tmpNd.Tag=drv["NodeId"].ToString();
tmpNd.Text=drv["NodeName"].ToString();
Nds.Add(tmpNd);
intId=drv["ParentId"].ToString();
InitTree(tmpNd.Nodes,tmpNd.Tag.ToString());
}
}
//新增节点操作
private void insert(string type)
{//判断是新增树节点,还是子节点.
string strinsert="insert into s_menu values('{0}','{1}','{2}')";
string strformat="";
if(type=="sub")
strformat=string.Format(strinsert,maxnodeid.ToString(),this.selectnode.Tag.ToString(),this.strcomm);
else
strformat=string.Format(strinsert,maxnodeid.ToString(),"0",this.strcomm);
SqlCommand cmd=new SqlCommand(strformat,this.sqlConnection1);
cmd.ExecuteNonQuery();
}
//为新增节点算出最大的节点值,并以此值作为新增的节点ID值
private int GetMaxNodeid()
{
int pre=0,last=0;
DataSet maxds=new DataSet();
this.sqlDataAdapter1=new SqlDataAdapter("select nodeid from s_menu order by nodeid",this.sqlConnection1);
this.sqlDataAdapter1.Fill(maxds);
for(int i=0;i{
if(i+1{
pre=int.Parse(maxds.Tables[0].Rows[i][0].ToString());
last=int.Parse(maxds.Tables[0].Rows[i+1][0].ToString());
if(last-pre!=1)
return pre+1;
}
}
return last+1;
}
private void getallnode(TreeNode tn)
{
foreach(TreeNode node in tn.Nodes)
{
list.Add(node.Tag.ToString());
if(node.Nodes.Count>0)
{
getallnode(node);
}
}
}

private void treeView1_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
{
//判断是否点击了某个节点
this.selectnode= this.treeView1.GetNodeAt (e.X ,e.Y );
if(selectnode==null)
this.isselected=false;
else
this.isselected=true;
}
private void menuAdd_Click(object sender, System.EventArgs e)
{//判断是否点击了某个节点,若没有点击了,则是新增一个树节点
if(isselected==false)
{//算出新增树节点的ID值
maxnodeid=GetMaxNodeid();
TreeNode tmpNd=new TreeNode();
//赋值
tmpNd.Tag=this.maxnodeid.ToString();
FormCommon frmCommon=new FormCommon();
DialogResult result= frmCommon.ShowDialog();
if(result==DialogResult.OK)
{//取到新增树节点的文本值
tmpNd.Text=frmCommon.strcomm;
this.strcomm=frmCommon.strcomm;
//新增树节点
this.treeView1.Nodes.Add(tmpNd);
//插入数据库(说明插入的是树节点)
this.insert("root");
//展开
this.selectnode.Expand();
}
}
else
{//判断是否点击了某个节点,若点击了,则是新增一个子节点
this.contextAddSub();
}
}
private void contextAddSub()
{//得到新增子节点的ID值
maxnodeid=GetMaxNodeid();
TreeNode tmpNd=new TreeNode();
//赋值
tmpNd.Tag=this.maxnodeid.ToString();
FormCommon frmCommon=new FormCommon();
DialogResult result= frmCommon.ShowDialog();
if(result==DialogResult.OK)
{//取到新增树节点的文本值
tmpNd.Text=frmCommon.strcomm;
this.strcomm=frmCommon.strcomm;
//新增子节点
this.selectnode.Nodes.Add(tmpNd);
//插入数据库(说明插入的是子节点)
this.insert("sub");
//展开
this.treeView1.SelectedNode.Expand();
}
}
//删除节点操作
private void menuDel_Click(object sender, System.EventArgs e)
{//新建一个ArrayList,用于保存要删除的节点下边的所有子节点
list=new ArrayList();
if(this.isselected==true)
{//得到删除的节点下边的所有子节点
getallnode(this.selectnode);
//把要删除的节点也加进去
list.Add(this.selectnode.Tag.ToString());
//循环从数据库中删除
for(int i=0;i{
string strdel="delete s_menu where nodeid='{0}'";
string strformat="";
strformat=string.Format(strdel,list[i]);
SqlCommand cmd=new SqlCommand(strformat,this.sqlConnection1);
cmd.ExecuteNonQuery();
}
//从树中删除
this.selectnode.Remove();
}
}
//修改节点的值
private void menuEdit_Click(object sender, System.EventArgs e)
{
if(this.isselected==true)
{
FormCommon frmCommon=new FormCommon();
DialogResult result= frmCommon.ShowDialog();
if(result==DialogResult.OK)
{
string strdel="update s_menu set nodename= '{1}' where nodeid='{0}'";
string strformat="";
strformat=string.Format(strdel,this.selectnode.Tag.ToString(),frmCommon.strcomm);
SqlCommand cmd=new SqlCommand(strformat,this.sqlConnection1);
cmd.ExecuteNonQuery();
this.selectnode.Text=frmCommon.strcomm;
}
}
}
//遍历所有节点.查找值
private void getvaluenode(TreeNodeCollection tn,string value)
{
foreach(TreeNode node in tn)
{
if(node.Nodes.Count>0)
{
getvaluenode(node.Nodes,value);
}
if(node.Text==value)
listnode.Add(node);
}
}
private void menuSearch_Click(object sender, System.EventArgs e)
{
int j,k;
this.listnode=new ArrayList();
FormCommon frmCommon=new FormCommon();
DialogResult result= frmCommon.ShowDialog();
if(result==DialogResult.OK)
{
TreeNode n =new TreeNode();
TreeNode temp=new TreeNode();
//下面的函数是填充listnode;
getvaluenode(this.treeView1.Nodes,frmCommon.strcomm);
for(int i=0;i{
j=0;k=0;
n=(TreeNode)listnode[i];
if (n != null)
{
temp=n;
//得到上面结点的数量,并将数量保存到变量j;
for(;n.Parent!=null;)
{
n=n.Parent;
j++;
}
//恢复原值
n=temp;
//新建一个树结点数组做保存得到查询到的所有节点.
TreeNode[] m=new TreeNode[j];
for(;n.Parent!=null;)
{
n=n.Parent;
m[k]=n;
k++;
}
for(int p=0;pm[p].Expand();
n=temp;
n.ForeColor=Color.Red;
}
}
}
}
private void treeView1_AfterLabelEdit(object sender, System.Windows.Forms.NodeLabelEditEventArgs e)
{
if(this.treeView1.SelectedNode.Text!=null)
{
string strdel="update s_menu set nodename= '{1}' where nodeid='{0}'";
string strformat="";strformat=string.Format(strdel,this.treeView1.SelectedNode.Tag.ToString(),e.Label.ToString());SqlCommand cmd=new SqlCommand(strformat,this.sqlConnection1);
cmd.ExecuteNonQuery();

}
}
private void treeView1_AfterSelect(object sender, System.Windows.Forms.TreeViewEventArgs e)
{
this.listBox1.Items.Clear();
this.listBox1.Items.Add(this.treeView1.SelectedNode.FullPath.ToString());
}
}
}