将对象转换为按钮 [英] Casting of Object to Button
问题描述
我有以下点击事件处理程序
//点击事件
public void ProcessClick（对象aoSender，EventArgs
aoArgs）
{
MessageBox.Show（" Clicked on" +（（Button）
aoSender）.Tag.ToString（） ）;
}
当我编译时我得到以下错误
"错误CS0029：无法隐式转换类型''对象''
到''System.Windows.Forms.Button''
我在这里做错了什么？
谢谢
您确定该行发生错误吗？
-
Miha Markic - RightHand .NET咨询&开发
miha at rthand com
www.rhand.com
" br" <一个******* @ discussions.microsoft.com>在消息中写道
news：04 **************************** @ phx.gbl ... < blockquote class =post_quotes>我有以下Click事件处理程序
// Click事件
public void ProcessClick（Object aoSender，EventArgs
aoArgs）
{<消息框.Show（" Clicked on" +（（Button）
aoSender）.Tag.ToString（））;
}
当我编译时得到以下错误
错误CS0029：无法隐式转换类型''对象''
到''System.Windows.Forms.Button''
我在做什么错了吗？
谢谢
br< an ******* @ discussion.microsoft.com>写道：我有以下点击事件处理程序
//点击事件
public void ProcessClick（Object aoSender，EventArgs
aoArgs）
{
MessageBox.Show（" Clicked on" +（（Button）
aoSender）.Tag.ToString（））;
}
及时我编译我得到以下错误
错误CS0029：无法隐式转换类型''对象''
到''System.Windows.Forms.Button''
什么我在这里做错了吗？
您发布的代码没有问题 - 您确定
编译器在抱怨那条线？
-
Jon Skeet - < sk *** @ pobox.com>
http://www.pobox.com/~skeet
如果回复小组，请不要给我发邮件
br写道：
我是什么在这里做错了吗？
没什么。但是，作为替代方案，你可以考虑这个：
按钮按钮=发送者为按钮;
if（按钮！= null）
{
//做你的东西
}
这可以防止出现转换错误的可能性。顺便说一句，为什么当按钮有很多其他标识属性时，使用标签
？
-
有10种人那些懂二元的人和那些没有b $ b的人。
http://code.acadx.com
（拉针回复）
I have the following Click event handler
//Click event
public void ProcessClick (Object aoSender, EventArgs
aoArgs)
{
MessageBox.Show ("Clicked on " + ((Button)
aoSender).Tag.ToString());
}
and when I compile I get the following error
"error CS0029: Cannot implicitly convert type ''object''
to ''System.Windows.Forms.Button''
What am I doing wrong here?
Thanks
Hi,
Are you sure that error occurs at that line?
--
Miha Markic - RightHand .NET consulting & development
miha at rthand com
www.rhand.com
"br" <an*******@discussions.microsoft.com> wrote in message
news:04****************************@phx.gbl...I have the following Click event handler
//Click event
public void ProcessClick (Object aoSender, EventArgs
aoArgs)
{
MessageBox.Show ("Clicked on " + ((Button)
aoSender).Tag.ToString());
}
and when I compile I get the following error
"error CS0029: Cannot implicitly convert type ''object''
to ''System.Windows.Forms.Button''
What am I doing wrong here?
Thanks
br <an*******@discussions.microsoft.com> wrote:I have the following Click event handler
//Click event
public void ProcessClick (Object aoSender, EventArgs
aoArgs)
{
MessageBox.Show ("Clicked on " + ((Button)
aoSender).Tag.ToString());
}
and when I compile I get the following error
"error CS0029: Cannot implicitly convert type ''object''
to ''System.Windows.Forms.Button''
What am I doing wrong here?
There''s nothing wrong with the code you posted - are you sure the
compiler is complaining about that line?
--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too
br wrote:
What am I doing wrong here?
Nothing. However, as an alternative you might consider this:
Button button = sender as Button;
if (button != null)
{
// do your thing
}
This prevents the possibility of a casting error. BTW, why use the tag
when a button has so many other identifying properties?
--
There are 10 kinds of people. Those who understand binary and those who
don''t.
http://code.acadx.com
(Pull the pin to reply)
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