如何连锁采购

Question

嗨，我正在尝试连锁跟踪订阅。

  changeBranch() {
const bottomSheetRef: MatBottomSheetRef = this.bottomSheet.open(CCSBranchComponent, {
  data: this.branches
});
this.subscription.add(bottomSheetRef.instance.change.subscribe((branch: Branch) => {
  this.branchInfo = `Description : ${branch.author}\nAuthor : ${branch.id}\nCreated date :${branch.created}`;
  this.blockpointBranchForm.get('branch').setValue(branch.id);
}));
this.subscription.add(bottomSheetRef.afterDismissed().subscribe(() => {
this.returnSelectedBranch.emit(this.blockpointBranchForm.get('branch').value);
}));

}

在这里，如果在加载表之前调用了bottomSheetRef.instance.change.subscribe，那么它会抛出未定义的。所以我正在尝试像这样的工具

this.subscription.add(this.bottomSheet.open(CCSBranchComponent, {
  data: this.branches
}).instance.change.subscribe((branch: Branch) => {
  this.branchInfo = `Description : ${branch.author}\nAuthor : ${branch.id}\nCreated date :${branch.created}`;
  this.blockpointBranchForm.get('branch').setValue(branch.id);
}).afterDismissed().subscribe(() => {
this.returnSelectedBranch.emit(this.blockpointBranchForm.get('branch').value);
}));

在这里，第二个订阅首先对订阅返回进行调用。如何访问链中可观察到的信息？

Answer 1

我想你想要的是把订阅时所做的动作链锁起来。

你可以通过

bottemsheetRef.instance.change.pipe(
 switchmap(resultFromChange => bottomSheetRef.afterDismissed
).subsbribe(resultFromAfterDismissed => {// do whatever you like})