Question

我有一个名为protected void btnSave_Click(object sender, EventArgs e) { player _player = new player(); Guid id = new Guid(Request.QueryString["id"].ToString()); Guid teamId = new Guid(Request.QueryString["teamId"].ToString()); if (teamId != Guid.Empty) _player.teamId = teamId; if (id == Guid.Empty) { _player.Name = txtFullName.Text; _player.address = txtAddress.Text; _player.player_id = _dal.GetNextPlayerId(16, 45); _player.gender = dlGenders.SelectedValue.ToString(); _dal.SoccerEntities.AddToplayers(_player); _dal.SoccerEntities.SaveChanges(); Response.Redirect("default.aspx"); } else { Guid _playerId = new Guid(Request.QueryString["id"].ToString()); _player = _dal.GetPlayerBYID(_playerId); if (_player.player_id == "") _player.player_id = _dal.GetNextPlayerId(16, 45); _player.gender = dlGenders.SelectedValue.ToString(); _player.Name = txtFullName.Text; _player.address = txtAddress.Text; _player.player_id = _dal.GetNextPlayerId(16, 45); _player.gender = dlGenders.SelectedValue.ToString(); if (teamId != Guid.Empty) _player.teamId = teamId; _dal.SoccerEntities.SaveChanges(); Response.Redirect("default.aspx"); }的状态键，其值可以在0到100之间。有没有办法可以对这些值进行约束？

知道我做了一个新方法（但它看起来过度工程）：

```

zoom

是否有更优雅的解决方案将约束应用于状态键？

Answer 1

最好的方法取决于约束的复杂性。

如果约束非常简单，你可以内联，就像这样：

this.setState ( { zoom : min(100, max(value, 0)) } );

更具可读性：

var validatedZoom = min(100, max(value, 0));
this.setState( { zoom : validatedZoom } );

如果验证更复杂（例如为用户生成消息）或验证需要可重用，则单独的验证功能可能是最好的方法。在简单的例子中：

function validatedZoom(value) {
  return min(100, max(value, 0));
}
// elsewhere
this.setState( { zoom : validatedZoom(value) } );

或@janakastevens提供的答案

Answer 2

它可能看起来像这样。

＆＃13;

handleOnChange(event){
  var newValue = this.checkZoomValue(event.target.value);
  this.setState({zoom:newValue});
}
checkZoomValue(value) {
  var outValue = min(value, 100)
  outValue = max(value, 0);
  return outValue;
}

＆＃13;

React.js中状态值的约束

2 个答案: