// DBTREEVIEW Detailed design .CPP file
__fastcall tdbtreeview :: TDBTREEVIEW (Tcomponent * Owner)
: TTREEVIEW (OWNER)
{
/ / Initialize the relevant data in the constructor
FDATALINK = New TfieldDataLink; // Establish a data connection class
Fparentidfield = ""; // Set the node father ID
FPRIMARYIDFIELD = ""; // Set the node master identity to empty
Fdisplayfield = ""; // Set the display field to empty
Factive = false; // Set to non-active status
FallowModifyDB = false; // Setting the data set is not allowed to modify
}
__fastcall tdbtreeView :: ~ tdbtreeview ()
{// Release the resource allocated in the destructor
DELETE FDATALINK; / / Release Data Connection Class
}
Void __fastcall tdbtreeview :: setActive (Bool Value)
{
/ / Set the status is activity
If (Factive! = Value) // If the specified state is the same as the current state, do not process, return directly
{//otherwise
If (value) // If the specified value is true
{
IF (fdataLink-> DataSource == NULL) // If you do not specify a data source, an exception is thrown
Throw Exception ("Missing Datasource Property.");
IF (fdataLink-> DataSource-> DataSet == NULL) / / Otherwise, if the data set is not specified in the data source, an exception is also thrown
Throw Exception ("INVALID DATASOURCE.");
If (fparentidfield == ") // If the parent identity field is empty, throw an exception
Throw Exception ("Missing ParentidField Property);
If (fprimaryidfield == ") // If the primary identification field is empty, throw an exception
Throw Exception ("Missing Primaryidfield Property.");
If (fdisplayfield == ") // If the display field is empty, an exception is thrown
Throw Exception ("Missing DisplayField Property.");
// Supplementary description: From the above exceptions, you should not see the environment you need to this component:
/ / Must specify the data source, dataset, node parent identification field, primary sign field, display field
CLEARALLNODES (); // Delete all nodes
FillTreenodes (0, null); // Plug all data to each node
}
Else
{// If the specified value is false
CLEARALLNODES (); // Delete all nodes
}
Factive = value; // Assign the specified value to Factive
}
}
Void __fastcall tdbtreeview :: setDataSource (DB :: TDataSource * Value)
{// set data source
IF (value! = fdataLink-> DataSource) // If the specified value is different from the current value,
{
FdataLink-> DataSource = value; // Set the current value of the data to the specified value}
}
TDataSource * __fastcall tdbtreeview :: getDataSource ()
{// Get data source
Return fdataLink-> DataSource; // Return to the data source
}
Void __fastcall tdbtreeview :: clearllnodes ()
{// Remove all nodes, call the related method of TreeView to translate the selection node delete
For (int i = 0; I
Delete (TDBTREENODEDATA *) (Items-> Item [i] -> data);
This-> items-> beginupdate ();
This-> items-> clear ();
This-> items-> endupdate ();
}
Void __fastcall tdbtreeview :: Filltreenodes (int ParentID, Ttreenode * Node)
{// Plip data to node
TQuery * AQuery = New TQuery (this); // Create a data set control
ANSISUSTRING STRSQL, STRTEXT;
INT IID, IParentID;
Int iimageIndex, IselectedIndex;
TTREENODE * TREENODE;
TDBTREENODEDATA NODEDATA;
// open the relevant data table with the specified condition
AQuery-> DatabaseName = ((ttable *) (fdataLink-> DataSource-> Dataset) -> DatabaseName;
AQuery-> Close (); // Turns off the data set
AQuery-> sql-> clear (); // Empty the original query condition
strsql = "SELECT *" ((Ttable *) (fdataLink-> DataSource-> Dataset) -> Tablename "Where";
STRSQL = fparentidfield "=: pid";
AQuery-> sql-> add (strsql); // Specify new query conditions
AQuery-> parambyname ("pid") -> asinteger = parentID; // get the parent identification field content
AQuery-> Open (); // Open Data Set
this-> items-> beginupdate (); // Preparing to update DBTREEVIEW display
While (! AQuery-> EOF) // Data does not go to the data intent, then
{
Strtext = AQuery-> FieldByName (fdisplayfield) -> asstring; // get the display field content
IID = AQUERY-> FieldByName (fPrimaryIDfield) -> asinteger; // get the primary identification field content
iParentID = AQUERY-> FieldByName (fparentidfield) -> asinteger; // get the parent identification field content
Treenode = this-> items-> addchild (node, strtext); // Add this sub-node
IIMAGEINDEX = ISELECTEDINDINDEX = -1; // Set node bitmap and selection time bitmap set to empty (-1)
IF (FonsetImageIndex) FonsetImageIndex (this, IID, iParentID, Treenode-> Level, IIMAGEX, ISELECTEDINDEX); // Trigger related events if the bitmap setting changes
Treenode-> ImageIndex = iimageIndex; // Setting the node bitmap and the bitmap
Treenode-> SELECTEDINDEX = ISELECTEDINDEX;
NodeData.id = IID; // Set node identity and parent identity
NodeData.parentId = iParentID;
AddDataTonode (Treenode, NodeData); // Add data to the specified node
FillChildtreenodes (IID, TREENODE, FALSE); // Fill child nodes
AQuery-> Next (); // Move to the next record
}
this-> items-> endupdate (); // Update DBTREEVIEW components
AQuery-> Close (); // Turns off the data set
Delete aquery; / / Delete temporary created data set controls
}
"Not complete"
