listbox.htm

网上商城的设计与实现

// ************************************************************************<BR>
// Microsoft Script Library<BR>
// Visual InterDev 6.0 Listbox Object for DHTML<BR>
// Copyright 1998 Microsoft Corporation. All Rights Reserved.<BR>
// <B>Do not modify in design view. Switch to source view.</B><BR>
// ************************************************************************<BR>
// <SCRIPT>
function CreateListbox(strName,funcInit,objParent)
{
	if (typeof(strName) != 'string' || strName == '')
		return null;

	// create SELECT tag in document
	var strTag = '<SELECT name="' + strName + '" id="' + strName + '" size=1></SELECT>'
	if ((typeof(objParent) == 'object') && (objParent != null))
		objParent.insertAdjacentHTML('BeforeEnd',strTag);
	else
		document.write(strTag);

	var objSelect = document.all[strName];
	if (typeof(objSelect) != 'object')
		return null;
	var bNameExists = eval('typeof(' + strName + ') == "object"');
	if (!bNameExists)	
		eval(strName + ' = objSelect');

	//events
	LB_ONCHANGE = 'onchange';
	
	// intrinsic properties
	//		name AND id		RO
	//		disabled		RW
	//		size			RW
	//		selectedIndex	RW

	// extended methods
	objSelect.isVisible	= _LB_isVisible;
	objSelect.show = _LB_show;
	objSelect.hide = _LB_hide;
	objSelect.addItem = _LB_addItem;
	objSelect.removeItem = _LB_removeItem;
	objSelect.clear = _LB_clear;
	objSelect.getCount = _LB_getCount;
	objSelect.getValue = _LB_getValue;
	objSelect.setValue = _LB_setValue;
	objSelect.getText = _LB_getText;
	objSelect.setText = _LB_setText;
	objSelect.selectByValue = _LB_selectByValue;
	objSelect.selectByText = _LB_selectByText;
	objSelect.getRowSource = _LB_getRowSource;
	objSelect.setRowSource = _LB_setRowSource;
	objSelect.getDataSource = _LB_getDataSource;
	objSelect.setDataSource = _LB_setDataSource;
	objSelect.getDataField = _LB_getDataField;
	objSelect.setDataField = _LB_setDataField;
	objSelect.advise = _LB_advise;
	objSelect.adviseDefaultHandler = _LB_adviseDefaultHandler;
	objSelect.unadvise = _LB_unadvise;
	objSelect.display = _LB_display;


	//private members
	objSelect._objRowSource = null;
	objSelect._objDataSource = null;
	objSelect._dataField = '';
	objSelect._fireEvent = _LB__fireEvent;

	// advise for default eventhandlers
	objSelect._objEventManager = CreateEventManager();
	objSelect._fireEvent('_LB__onbeforefuncinit(' + objSelect.id + ')');
	objSelect._fireEvent(funcInit);
	return objSelect;
}

function _LB_isVisible()
{	return (this.style.visibility != 'hidden');	}

function _LB_show()
{	this.style.visibility = 'visible';	}

function _LB_hide()
{	this.style.visibility = 'hidden';	}

function _LB_addItem(strText,value,nIndex)
{	
	var nCount = this.getCount();
	if (typeof(value) == 'undefined')
		value = strText;
	if (typeof(nIndex) == 'undefined')
		nIndex = nCount;
	if (!isNaN(parseInt(nIndex)))
	{	// add item at given nIndex
		var opt = document.createElement('OPTION');
		opt.text = String(strText);
		opt.value = value;
		if (nIndex < 0)		// add as first item in list
			nIndex = 0;
		if (nIndex < nCount)
		{	// insert item at given index
			this.add(opt,nIndex);
			return nIndex;
		}	
		else
		{	// add item to end of list
			this.add(opt);
			return nCount;		
		}
	}
	return -1;	// failed to add item
}

function _LB_removeItem(nIndex)
{	
	if (typeof(nIndex) == 'undefined')
		nIndex = this.selectedIndex;
	if (!isNaN(parseInt(nIndex)) && nIndex >= 0 && nIndex < this.getCount())
	{	// remove item at nIndex
		this.options.remove(nIndex);
		return true;
	}
	return false;
}

function _LB_clear()
{	this.options.length = 0;	}

function _LB_getCount()
{	return this.options.length;	}

function _LB_getValue(nIndex)
{
	if (typeof(nIndex) == 'undefined')
		nIndex = this.selectedIndex;
	if (!isNaN(parseInt(nIndex)) && nIndex >= 0 && nIndex < this.getCount())
		return this.item(Number(nIndex)).value;
	return '';
}

function _LB_setValue(value,nIndex)
{
	if (typeof(nIndex) == 'undefined')
		nIndex = this.selectedIndex;
	if (!isNaN(parseInt(nIndex)) && nIndex >= 0 && nIndex < this.getCount())
	{
		this.item(Number(nIndex)).value = value;
		return true;
	}
	return false;
}

function _LB_getText(nIndex)
{
	if (typeof(nIndex) == 'undefined')
		nIndex = this.selectedIndex;
	if (!isNaN(parseInt(nIndex)) && nIndex >= 0 && nIndex < this.getCount())
		return this.item(Number(nIndex)).text;
	return '';
}

function _LB_setText(strText,nIndex)
{
	if (typeof(nIndex) == 'undefined')
		nIndex = this.selectedIndex;
	if (!isNaN(parseInt(nIndex)) && nIndex >= 0 && nIndex < this.getCount())
	{
		this.item(Number(nIndex)).text = String(strText);
		return true;
	}
	return false;
}
	
function _LB_selectByValue(value)
{
	for (var i=0; i < this.getCount(); i++)
	{
		if (value == this.options(i).value)
		{
			this.selectedIndex = i;
			return i;
		}
	}
	return -1;
}

function _LB_selectByText(strText)
{	
	for (var i=0; i < this.getCount(); i++)
	{
		if (strText == this.options(i).text)
		{
			this.selectedIndex = i;
			return i;
		}
	}
	return -1;
}
	
function _LB_getRowSource()
{	return this._objRowSource;	}

function _LB_setRowSource(objRecordset,listField,boundField)
{	
	if (typeof(objRecordset) == 'object' && this.getCount() == 0)
	{	// only allow setting one lookup source to be consistent with server
		var nPos = objRecordset.absolutePosition;
		this._objRowSource = objRecordset;
		objRecordset.moveFirst();
		while (!objRecordset.EOF)
		{
			var objFields = objRecordset.fields;
			this.addItem(objFields.getValue(listField),objFields.getValue(boundField));
			objRecordset.moveNext();
		}
		objRecordset.moveAbsolute(nPos);
		return true;
	}	
	return false;
}

function _LB_getDataSource()
{	return this._objDataSource;		}

function _LB_setDataSource(objDataSource)
{
	if (typeof(objDataSource) != 'object')
		return false;

	if ((this._objDataSource != null) && (this._dataField != ''))
	{
		if (this._objDataSource.isDHTMLAware())
		{
			this.dataSrc = '';
			this.dataFld = '';
		}
		else
		{
			this._objDataSource.unadvise(this._rowEnterID);
			this._objDataSource.unadvise(this._rowExitID);
		}
	}
	
	if ((this._objDataSource == null) || (objDataSource != null && this._objDataSource.id != objDataSource.id))
	{
		if (this._objDataSource != null)
			this._objDataSource.unadvise(this._afterOpenID);
			
		this._afterOpenID = objDataSource.advise(RS_ONAFTEROPEN, this.id + '.setDataSource(' + objDataSource.id + ');');
	}

	this._objDataSource = objDataSource;
	if ((objDataSource != null) && (this._dataField != ''))
	{
		if (objDataSource.isDHTMLAware())
		{
			this.dataSrc = '#' + objDataSource.getDHTMLDataSourceID();
			this.dataFld = this._dataField;
		}	
		else
		{
			this._rowEnterID = objDataSource.advise(RS_ONROWENTER, '_LB__onrowenter(' + objDataSource.id + ', ' + this.name + ', "' + this._dataField + '");');
			this._rowExitID = objDataSource.advise(RS_ONROWEXIT, '_LB__onrowexit(' + objDataSource.id + ', ' + this.name + ', "' + this._dataField + '");');
		}
	}		
	return true;
}	
	
function _LB_getDataField()
{	return this._dataField;		}

function _LB_setDataField(dataField)
{
	if ((this._objDataSource != null) && (this._dataField != ''))
	{
		if (this._objDataSource.isDHTMLAware())
		{
			this.dataSrc = '';
			this.dataFld = '';
		}
		else
		{
			this._objDataSource.unadvise(this._rowEnterID);
			this._objDataSource.unadvise(this._rowExitID);
		}
	}

	this._dataField = dataField;
	if ((this._objDataSource != null) && (this._dataField != ''))
	{	
		if (this._objDataSource.isDHTMLAware())
		{
			this.dataSrc = '#' + this._objDataSource.getDHTMLDataSourceID();
			this.dataFld = dataField;
		}	
		else
		{
			this._rowEnterID = this._objDataSource.advise(RS_ONROWENTER, '_LB__onrowenter(' + this._objDataSource.id + ', ' + this.name + ', "' + dataField + '");');
			this._rowExitID = this._objDataSource.advise(RS_ONROWEXIT, '_LB__onrowexit(' + this._objDataSource.id + ', ' + this.name + ', "' + dataField + '");');
		}
	}		
	return true;
}

function _LB_advise(strEvent,funcToCall)
{
	var nAdviseID = this._objEventManager.advise(strEvent,funcToCall);
	if (nAdviseID != -1)
		eval('this.' + strEvent + ' = _LB__fireEvent;');
}

function _LB_adviseDefaultHandler(strName,strEvent)
{
	var nAdviseID = this._objEventManager.adviseDefaultHandler(strName,strEvent);
	if (nAdviseID != -1)
		eval("this." + strEvent + " = _LB__fireEvent;");
}

function _LB_unadvise(strEvent,nAdviseID)
{
	return this._objEventManager.unadvise(strEvent,nAdviseID);
}

function _LB_display()		// do nothing for DHTML case
{	}

function _LB__fireEvent(funcToFire)
{
	if (typeof(funcToFire) == 'undefined')
	{
		if (this._objEventManager != null)
			this._objEventManager.fireEvent('on' + window.event.type);
	}
	else
		_EM__fireEvent(funcToFire);
}

function _LB__onrowenter(objRecordset,objListbox,dataField)
{
	objListbox.select(objRecordset.fields.getValue(dataField) + '');
	return true;
}

function _LB__onrowexit(objRecordset,objListbox,dataField)
{
	var selValue = objListbox.getValue();
	if (selValue != null && selValue != 'undefined')
		objRecordset.fields.setValue(selValue);
	return true;
}

function _LB__onbeforefuncinit(objListbox)
{	objListbox.adviseDefaultHandler(objListbox.id, LB_ONCHANGE);	}