如何防止创建空文件
如果每个项目的radioButton为“是”,我有一个基于Repeater控件中的项目创建的文件。我的问题是,如果文件是空的,它仍然在创建。我试过FileName.Length> 0和其他可能的解决方案,但我得到的错误,该文件无法找到。我相信这个问题是在我的逻辑之内,但我不知道在哪里。有任何想法吗?如何防止创建空文件
protected void btnContinue_Click(object sender, EventArgs e)
{
string JobName;
string FileName;
StreamWriter sw;
string Name, Company, Date;
JobName = TYest + "_" + System.DateTime.Now;
JobName = JobName.Replace(":", "").Replace("/", "").Replace(" ", "");
FileName = JobName + ".txt";
sw = new StreamWriter(C: +"/" + FileName, false, Encoding.GetEncoding(1250));
foreach (RepeaterItem rpItems in rpGetData.Items)
{
RadioButtonList rbYesNo = (RadioButtonList)rpItems.FindControl("rbBadge");
if (rbYesNo.SelectedItem.Text == "Yes")
{
Label rName = (Label)rpItems.FindControl("lblName");
Label rCompany = (Label)rpItems.FindControl("lblCompany");
Label rFacilityName = (Label)rpItems.FindControl("lblFacility_Hidden");
Name = rName.Text;
Company = rCompany.Text;
Date = System.DateTime.Now.ToString("MM/dd/yyyy");
sw.WriteLine("Name," + Name);
sw.WriteLine("Company," + Company);
sw.WriteLine("Date," + Date);
sw.WriteLine("*PRINTLABEL");
}
sw.Flush();
sw.Dispose();
if (File.Exists("C:/" + FileName))
{
try
{
File.Copy(+"C:/" + FileName, LoftwareDropPath + FileName, true);
}
catch (Exception ex)
{
string msgE = "Error";
msgE += ex.Message;
throw new Exception(msgE);
}
}
else
{
//Do something if temp file not created properly
lblMessage.Text = "An error has occurred. Plese see your host to get a printed name badge.";
}
MessageBox messageBox = new MessageBox();
messageBox.MessageTitle = "Printed?";
messageBox.MessageText = "If not, please see host.";
Literal1.Text = messageBox.Show(this);
}
}
听起来像要检测文件是否为空。用途:
long length = new System.IO.FileInfo(path).Length;
if(length == 0)....
FileName.Length
只是告诉你的文件名是多久 - 不usefule
如果文件存在第一为什么不签?这应该解决你的异常问题!如果您想知道文件是否为空,我会建议您检查一下您正在写入的文件,并确保它并非全部为空,并且如果您确实有内容,请写入该文件?
if(File.Exists(File))
{
if(new FileInfo(File).Length > 0)
{
//Do Stuff.
}
}
您应该将其更改为仅在写入一些数据时才写入和创建文件。
这样做的一个简单方法是存储的一切记忆的东西,如一个StringBuilder
,然后事后字符串生成器的内容写入文件,如果有东西可写:这个怎么样
var sb = new StringBuilder();
foreach (RepeaterItem rpItems in rpGetData.Items)
{
RadioButtonList rbYesNo = (RadioButtonList)rpItems.FindControl("rbBadge");
if (rbYesNo.SelectedItem.Text == "Yes")
{
// ..omitted..
sb.AppendLine("Name," + Name);
sb.AppendLine("Company," + Company);
sb.AppendLine("Date," + Date);
sb.AppendLine("*PRINTLABEL");
}
}
if (sb.Length > 0)
{
File.WriteAllText(FileName, sb.ToString(), Encoding.GetEncoding(1250));
}
:
StreamWriter sw = null;
string Name, Company, Date;
JobName = TYest + "_" + System.DateTime.Now;
JobName = JobName.Replace(":", "").Replace("/", "").Replace(" ", "");
FileName = @"C:\" + JobName + ".txt";
try
{
foreach (RepeaterItem rpItems in rpGetData.Items)
{
RadioButtonList rbYesNo = (RadioButtonList)rpItems.FindControl("rbBadge");
if (rbYesNo.SelectedItem.Text == "Yes")
{
if (null == sw)
sw = new StreamWriter(FileName, false, Encoding.GetEncoding(1250));
Label rName = (Label)rpItems.FindControl("lblName");
Label rCompany = (Label)rpItems.FindControl("lblCompany");
Label rFacilityName = (Label)rpItems.FindControl("lblFacility_Hidden");
Name = rName.Text;
Company = rCompany.Text;
Date = System.DateTime.Now.ToString("MM/dd/yyyy");
sw.WriteLine("Name," + Name);
sw.WriteLine("Company," + Company);
sw.WriteLine("Date," + Date);
sw.WriteLine("*PRINTLABEL");
}
}
finally
{
if (null != sw)
{
sw.Flush();
sw.Dispose();
}
}
一次构建您的FileName,以便您知道它始终是相同的。然后只有在写入内容时才创建StreamWriter。此外,请使用try..finally来确保您的代码释放您的资源总是被击中。
您可以检查所有项目是否有资格开流作家喜欢在此之前节省:
var itemsToBeSaved = rpGetData.Items
Where(ri => ((RadioButtonList)ri.FindControl("rbBadge")).SelectedItem.Text == "Yes");
if (itemsToBeSaved.Any()) {
string path = @"C:\" + FileName;
using (var sw = new StreamWriter(path, false, Encoding.GetEncoding(1250))) {
foreach (RepeaterItem rpItems in itemsToBeSaved) {
Label rName = (Label)rpItems.FindControl("lblName");
Label rCompany = (Label)rpItems.FindControl("lblCompany");
Label rFacilityName = (Label)rpItems.FindControl("lblFacility_Hidden");
Name = rName.Text;
Company = rCompany.Text;
Date = System.DateTime.Now.ToString("MM/dd/yyyy");
sw.WriteLine("Name," + Name);
sw.WriteLine("Company," + Company);
sw.WriteLine("Date," + Date);
sw.WriteLine("*PRINTLABEL");
}
} // Flushes, Closes und Disposes the stream automatically.
}
第一条语句准备的只包含那些中继项的过滤枚举进行保存。 itemsToBeSaved.Any()
测试此枚举是否至少包含一个项目。此枚举然后在foreach语句中重用。因此没有必要再次检查条件。
即使在写入文件时发生异常,using语句也会在所有情况下关闭流。我还在using语句中声明了流编写器。因此您可以删除您的声明StreamWriter sw = null;
。
还注意到表达式@"C:\" + FileName
。 @
使字符串常量为逐字串。这意味着通常的转义字符'\'
失去其含义,并且如那样使用。 Path.Combine(...)
在这里不起作用,因为它不会在驱动器号后添加路径分隔符。
你看过可能创建文件的StreamWriter构造函数吗?另外,FileName.Length正在检查字符串,而不是文件本身,因为在任何地方你都没有一个变量是文件本身,而是你正在使用文件类中的方法。 –