This closes qax-os#1254, DeleteDataValidation support delete all da…

…ta validations in the worksheet

datavalidation.go

@@ -262,16 +262,21 @@ func (f *File) AddDataValidation(sheet string, dv *DataValidation) error {
 }
 
 // DeleteDataValidation delete data validation by given worksheet name and
-// reference sequence.
-func (f *File) DeleteDataValidation(sheet, sqref string) error {
+// reference sequence. All data validations in the worksheet will be deleted
+// if not specify reference sequence parameter.
+func (f *File) DeleteDataValidation(sheet string, sqref ...string) error {
 	ws, err := f.workSheetReader(sheet)
 	if err != nil {
 		return err
 	}
 	if ws.DataValidations == nil {
 		return nil
 	}
-	delCells, err := f.flatSqref(sqref)
+	if sqref == nil {
+		ws.DataValidations = nil
+		return nil
+	}
+	delCells, err := f.flatSqref(sqref[0])
 	if err != nil {
 		return err
 	}

datavalidation_test.go

@@ -171,4 +171,8 @@ func TestDeleteDataValidation(t *testing.T) {
 
 	// Test delete data validation on no exists worksheet.
 	assert.EqualError(t, f.DeleteDataValidation("SheetN", "A1:B2"), "sheet SheetN is not exist")
+
+	// Test delete all data validations in the worksheet
+	assert.NoError(t, f.DeleteDataValidation("Sheet1"))
+	assert.Nil(t, ws.(*xlsxWorksheet).DataValidations)
 }