Go exceed API source code reading (VI) -- deletesheet (sheet string)

Go-Excelize API Source code reading （ 6、 ... and ）—— DeleteSheet(sheet string)

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One 、Go-Excelize brief introduction

Excelize yes Go Language written for operation Office Excel Document base library , be based on ECMA-376,ISO/IEC 29500 international standard . You can use it to read 、 Written by Microsoft Excel 2007 Spreadsheet documents created by and above . Support XLAM / XLSM / XLSX / XLTM / XLTX And so on , Highly compatible with styles 、 picture ( surface )、 PivotTable 、 Slicer and other complex components of the document , And provide streaming reading and writing API, For workbooks that contain large amounts of data . It can be applied to various report platforms 、 Cloud computing 、 Edge computing and other systems . Required to use this class library Go The language is 1.15 Or later .

Two 、DeleteSheet(sheet string)

func (f *File) DeleteSheet(sheet string)

Delete the specified worksheet according to the given worksheet name , Use this method with caution , This will affect the formula associated with the deleted worksheet 、 quote 、 Chart and other elements . If other components refer to the values on the deleted worksheet , Will cause an error , It will even cause the workbook to fail to open . When the workbook contains only one worksheet , Invalid call to this method .

func (f *File) DeleteSheet(name string) {
    
	if f.SheetCount == 1 || f.GetSheetIndex(name) == -1 {
    
		return
	}
	sheetName := trimSheetName(name)
	wb := f.workbookReader()
	wbRels := f.relsReader(f.getWorkbookRelsPath())
	activeSheetName := f.GetSheetName(f.GetActiveSheetIndex())
	deleteLocalSheetID := f.GetSheetIndex(name)
	deleteAndAdjustDefinedNames(wb, deleteLocalSheetID)

	for idx, sheet := range wb.Sheets.Sheet {
    
		if !strings.EqualFold(sheet.Name, sheetName) {
    
			continue
		}

		wb.Sheets.Sheet = append(wb.Sheets.Sheet[:idx], wb.Sheets.Sheet[idx+1:]...)
		var sheetXML, rels string
		if wbRels != nil {
    
			for _, rel := range wbRels.Relationships {
    
				if rel.ID == sheet.ID {
    
					sheetXML = f.getWorksheetPath(rel.Target)
					rels = "xl/worksheets/_rels/" + strings.TrimPrefix(f.sheetMap[sheetName], "xl/worksheets/") + ".rels"
				}
			}
		}
		target := f.deleteSheetFromWorkbookRels(sheet.ID)
		f.deleteSheetFromContentTypes(target)
		f.deleteCalcChain(sheet.SheetID, "")
		delete(f.sheetMap, sheet.Name)
		f.Pkg.Delete(sheetXML)
		f.Pkg.Delete(rels)
		f.Relationships.Delete(rels)
		f.Sheet.Delete(sheetXML)
		delete(f.xmlAttr, sheetXML)
		f.SheetCount--
	}
	f.SetActiveSheet(f.GetSheetIndex(activeSheetName))
}

if f.SheetCount == 1 || f.GetSheetIndex(name) == -1 {
    
		return
	}

This code is to ensure that when the workbook contains only one worksheet , Or it is invalid to call this method when the name of the worksheet is incorrect .

func (f *File) GetSheetIndex(name string) int {
    
	for index, sheet := range f.GetSheetList() {
    
		if strings.EqualFold(sheet, trimSheetName(name)) {
    
			return index
		}
	}
	return -1
}

The above code shows ： When the of the worksheet is not in the worksheet list GetSheetIndex return -1.

sheetName := trimSheetName(name) The function of is to get the name of the worksheet .

func trimSheetName(name string) string {
    
	if strings.ContainsAny(name, ":\\/?*[]") || utf8.RuneCountInString(name) > 31 {
    
		r := make([]rune, 0, 31)
		for _, v := range name {
    
			switch v {
    
			case 58, 92, 47, 63, 42, 91, 93: // replace :\/?*[]
				continue
			default:
				r = append(r, v)
			}
			if len(r) == 31 {
    
				break
			}
		}
		name = string(r)
	}
	return name
}

It's not hard to see. , This API The function of is to cut \/?*[] These content .

	wb := f.workbookReader()
	wbRels := f.relsReader(f.getWorkbookRelsPath())

workbookReader Get the deserialized workbook.xml Structure pointer .
relsReader obtain xl/worksheets/_rels/sheet%d.xml.rels Deserialized structure pointer .

	activeSheetName := f.GetSheetName(f.GetActiveSheetIndex())
	deleteLocalSheetID := f.GetSheetIndex(name)
	deleteAndAdjustDefinedNames(wb, deleteLocalSheetID)

GetActiveSheetIndex Provides a function to get the active worksheet index of the spreadsheet .

If the active worksheet is not found , Will return an integer 0.

About ActiveSheet The content of can be found in Microsoft documentation ：

Workbook.ActiveSheet attribute (Excel) | Microsoft Docs
https://docs.microsoft.com/zh-cn/office/vba/api/excel.workbook.activesheet

activeSheetName Is the name of the active worksheet ,deleteLocalSheetID Is the current worksheet to delete ID.
deleteAndAdjustDefinedNames Through the given worksheet ID Delete and adjust the names defined in the workbook .

func deleteAndAdjustDefinedNames(wb *xlsxWorkbook, deleteLocalSheetID int) {
    
	if wb == nil || wb.DefinedNames == nil {
    
		return
	}
	for idx := 0; idx < len(wb.DefinedNames.DefinedName); idx++ {
    
		dn := wb.DefinedNames.DefinedName[idx]
		if dn.LocalSheetID != nil {
    
			localSheetID := *dn.LocalSheetID
			if localSheetID == deleteLocalSheetID {
    
				wb.DefinedNames.DefinedName = append(wb.DefinedNames.DefinedName[:idx], wb.DefinedNames.DefinedName[idx+1:]...)
				idx--
			} else if localSheetID > deleteLocalSheetID {
    
				wb.DefinedNames.DefinedName[idx].LocalSheetID = intPtr(*dn.LocalSheetID - 1)
			}
		}
	}
}

among , The following code is cleverly used ：

for idx, sheet := range wb.Sheets.Sheet {
    
		if !strings.EqualFold(sheet.Name, sheetName) {
    
			continue
		}

		wb.Sheets.Sheet = append(wb.Sheets.Sheet[:idx], wb.Sheets.Sheet[idx+1:]...)
		var sheetXML, rels string
		if wbRels != nil {
    
			for _, rel := range wbRels.Relationships {
    
				if rel.ID == sheet.ID {
    
					sheetXML = f.getWorksheetPath(rel.Target)
					rels = "xl/worksheets/_rels/" + strings.TrimPrefix(f.sheetMap[sheetName], "xl/worksheets/") + ".rels"
				}
			}
		}
		target := f.deleteSheetFromWorkbookRels(sheet.ID)
		f.deleteSheetFromContentTypes(target)
		f.deleteCalcChain(sheet.SheetID, "")
		delete(f.sheetMap, sheet.Name)
		f.Pkg.Delete(sheetXML)
		f.Pkg.Delete(rels)
		f.Relationships.Delete(rels)
		f.Sheet.Delete(sheetXML)
		delete(f.xmlAttr, sheetXML)
		f.SheetCount--
	}

This code is to delete sheetName The corresponding one sheet, The specific details will not be detailed .

f.SetActiveSheet(f.GetSheetIndex(activeSheetName)) Just continue to set up the active worksheet , It should be the previous activity table .

3、 ... and 、 Conclusion

This is Lao Yue , This is a Go Interpretation of language related source code Chapter 6 , I'll keep trying , Bring you more similar articles , Please give me your advice .