无法将 HiddenField 转换为 Int32 [英] Can not convert HiddenField to Int32

问题描述

我在数据类型转换方面遇到了问题，我只能弄清楚

I am having a problem with data type conversion that I just can figure out

 HiddenField hfFriendId = item.FindControl("hfFriendId") as HiddenField;
 Int32 FriendId = Convert.ToInt32(hfFriendId.Value);

我需要在下面使用FriendId as和int32

I need to use FriendId as and int32 in the following

UserInfo TargetUser = UserController.GetUserById(PortalSettings.PortalId, FriendId);

因为两个参数都应该是 int32.当我调试这个TargetUser"时为空.

as both args are expected to be int32. When I debug this 'TargetUser' is null.

可能是什么问题?

推荐答案

如果您不确定隐藏字段中可用的值，则不要使用

If you are not sure of the value available in the hiddenfield then instead of using

Int32 FriendId = Convert.ToInt32(hfFriendId.Value);

试试

int FriendId = int.Parse(hfFriendId.Value); // will throw exception if parse fails

或更好

int FriendId ;
if(int.TryParse(hfFriendId.Value, out FriendId))
     //get userinfo

也可能是您的 UserController.GetUserById 方法存在问题，以防 Convert 获取解析的值并且未返回零.

Also it could be an issue with your UserController.GetUserById method in case the Convert gets the value parsed and is not returning zero.

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