angular7 动态表单与验证

表单初始数据：

this.deviceForm = this.fb.group({
      name: ["", [Validators.required]],
      serialNumber: [""],
      modelname: [""], // 设备型号
      model: [""], // 型号
      modelId: ["", [Validators.required]], //模型ID
      make: [""], // 生成厂家
      model_memo: [""], // 备注
      iconType: ["", [Validators.required]], //类型
      mode: "",
      modename: "",
      subnet: ["", [this.validateSubnet]],
      devicePorts: this.fb.array([this.creatPort()])

表单联动改变：modelId 改变时，为make.和model_memo 赋值。当modelId为 -1时，新建model.

 formModelChangeEmit() {
    this.deviceForm.get("modelId").valueChanges.subscribe((value) => {
      if (value == -1) {
        this.modeShowChange(true)
      } else {
        let model = this.device.models.find((item) => item.modelId == value)
        if (model) {
          this.deviceForm.patchValue({
            make: model.make,
            model_memo: model.model_memo
          })
        }
      }
    })
  }

modeShowChange(show) {

    this.device.modeShow = show

    if (show) {

      this.deviceForm.patchValue({

        make: "",

        model_memo: ""

      })

    } else {

      this.deviceForm.patchValue({

        modelId: this.device.models[1].modelId

      })

    }

  }

表单IconType改变时，修改表单的control；这里使用removeControl和addControl 主要是为了解决from的valid状态问题。

formIcontypeChangeEmit() {
    this.deviceForm.get("iconType").valueChanges.subscribe((value) => {
      if (value == "subnet") {
        this.deviceForm.removeControl("modelId")
        this.deviceForm.removeControl("devicePorts")
        this.deviceForm.updateValueAndValidity()
        this.deviceForm
          .get("subnet")
          .setValidators([Validators.required, this.validateSubnet])
        this.subnetShow = true
      } else {
        this.deviceForm.get("subnet").setValidators(null)
        this.deviceForm.addControl(
          "modelId",
          new FormControl("", [Validators.required])
        )
        this.deviceForm.addControl(
          "devicePorts",
          this.fb.array([this.creatPort()])
        )
        this.formModelChangeEmit()
        this.subnetShow = false
      }
    })
  }