错误提供程序中的问题

问题描述

private void tbxWidthBackIamge_Validated(object sender, EventArgs e)
{
    this.errBackWidth.SetError(tbxWidthBackIamge, "Enter the Width");
    if (tbxBackImage.Text != "")
        this.errBackHeight.Dispose();
}

我使用errorProvider验证文本框.发生错误时显示.但是在更正错误后，它并没有消失.

I use an errorProvider to validate a textbox. It appears when there occurred an error. But It didn''t disappear after correct the error. Is any error in this code?

推荐答案

1. 使用Validat ing 事件
2. 在输入不正确时使用SetError(...，"ErrorMessage")
3. 使用SetError(.. .，string.Empty)输入正确时

1. Use the Validating event
2. Use SetError(..., "ErrorMessage") when the input is incorrect
3. Use SetError(..., string.Empty) when the input is correct

private void tbxWidthBackIamge_Validated(object sender, EventArgs e) {
    if (tbxBackImage.Text.Trim() == string.Empty)
       this.errBackWidth.SetError(tbxWidthBackIamge, "Enter the Width");
    else
       this.errBackWidth.SetError(tbxWidthBackIamge, string.Empty);
}

请注意，我用string.Empty代替了"(从不这样做).我还建议添加Trim，假定仅包含空格字符的字符串也是无效的.如果我的假设是错误的，只需删除Trim.

更好的是，使用匿名委托:

Pay attention, I use string.Empty instead of "" (never do it). I also suggest to add Trim assuming that a string containing only blank space characters is also invalid. If my assumption is wrong, simply remove Trim.

Better yet, use anonymous delegate:

myControl.Validated += delegate(object sender, System.EventArgs eventArgs) {
    if (tbxBackImage.Text.Trim() == string.Empty)
       this.errBackWidth.SetError(tbxWidthBackIamge, "Enter the Width");
    else
       this.errBackWidth.SetError(tbxWidthBackIamge, string.Empty);
}

在C#v.3或v.4中，您可以使用lambda形式的委托使用更好的语法:

With C# v.3 or v.4 you could use the even better syntax with lambda form of the delegate:

myControl.Validated += (sender, eventArgs) => {
    if (tbxBackImage.Text.Trim() == string.Empty)
       this.errBackWidth.SetError(tbxWidthBackIamge, "Enter the Width");
    else
       this.errBackWidth.SetError(tbxWidthBackIamge, string.Empty);
}

请参阅此MSDN帮助页面上的代码示例: http://msdn.microsoft. com/en-us/library/system.windows.forms.errorprovider.aspx [ ^ ].

您的代码甚至可以编译吗?我的意思是，您要配置的errBackHeight是什么.它实现IDisposable吗?为什么要对错误进行任何处理?只是检查.

—SA

See the code sample on this MSDN help page: http://msdn.microsoft.com/en-us/library/system.windows.forms.errorprovider.aspx[^].

Does your code even compile? I mean, what is errBackHeight which you dispose. Does it implement IDisposable? Why disposing anything on error? Just checking.

—SA

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