如何使用asp.net从文件夹中删除特定文件

here's the deal I got a datagridviewer which is called gridview1 and a fileupload1 when i upload a file it updates the gridview1 and table in database with the file name and path and stores the said file in folder "Mag"... but now what i want to do is the reverse i got how to use the gridview to delete the table entry but deleting the file from folder "Mag" is not working have used the following code in C# or codebehind

这里的交易我得到了一个datagridviewer，名为gridview1和fileupload1，当我上传文件时，它用文件名和路径更新gridview1和数据库中的表，并将所述文件存储在文件夹“Mag”中...但是现在我是什么想要做的是反过来我得到了如何使用gridview删除表条目但删除文件夹“Mag”无法正常使用C＃中的以下代码或代码隐藏

protected void GridView1_Del(object sender, EventArgs e)  
{
    string DeleteThis = GridView1.SelectedRow.Cells[0].Text;
    string[] Files = Directory.GetFiles(@"i:/Website/WebSite3/Mag/");

    foreach (string file in Files)
    {
        if (file.ToUpper().Contains(DeleteThis.ToUpper()))
        {
            File.Delete(file);
        }
    }
}

it gives me error

它给了我错误

"Object reference not set to an instance of an object."

“你调用的对象是空的。”

pls tell me what im doing wrong am new and don't have to in depth understanding of the platform so any and all help will be appreciated thanks in advance Mark

请告诉我，我做错了什么是新的，不必深入了解平台所以任何和所有的帮助将不胜感激提前感谢马克

Here is the answer i found Thanks Tammy and everyone else for all the answers

这是我发现的答案感谢Tammy和其他所有人的答案

Ok here the deal target function delete file details from gridview and database table and file from project folder where the file is stored

好的，交易目标函数从gridview和数据库表中删除文件详细信息，并从存储文件的项目文件夹中删除文件

in script section of gridview you would want to include

在gridview的脚本部分，你想要包括

OnRowDeleting="FuntionName"

Not

不

OnSelectedIndexChanged = "FuntionName"

or

要么

OnRowDeleted="FuntionName"

then in C# code(codebehind)

那么在C＃代码中（代码隐藏）

protected void FuntionName(object sender, GridViewDeleteEventArgs e)
    {
// storing value from cell
        TableCell cell = GridView1.Rows[e.RowIndex].Cells[0];

// full path required
        string fileName = ("i:/Website/WebSite3/Mag/" + cell.Text); 

    if(fileName != null || fileName != string.Empty)
    {
       if((System.IO.File.Exists(fileName))) 
       {
           System.IO.File.Delete(fileName);
       }

     }
  }

And just for added reference for those who want to learn

只是为那些想要学习的人提供了额外的参考

OnRowDeleting="FuntionName" is for just before deleting a row you can cancel deleting or run functions on the data like i did

OnRowDeleting =“FuntionName”就是在删除行之前你可以取消删除或运行数据上的函数，就像我做的那样

OnRowDeleted="FuntionName" it directly deletes

它直接删除OnRowDeleted =“FuntionName”

5 个解决方案

#1

This is how I delete files

这是我删除文件的方式

if ((System.IO.File.Exists(fileName)))
                {
                    System.IO.File.Delete(fileName);
}

Also make sure that the file name you are passing in your delete, is the accurate path

还要确保您在删除时传递的文件名是准确的路径

EDIT

编辑

You could use the following event instead as well or just use the code in this snippet and use in your method

您也可以使用以下事件，或者只使用此代码段中的代码并在您的方法中使用

void GridView1_SelectedIndexChanged(Object sender, EventArgs e)
  {

    // Get the currently selected row using the SelectedRow property.
    GridViewRow row = CustomersGridView.SelectedRow;

    //Debug this line and see what value is returned if it contains the full path.
    //If it does not contain the full path then add the path to the string.
    string fileName = row.Cells[0].Text 

    if(fileName != null || fileName != string.empty)
    {
       if((System.IO.File.Exists(fileName))
           System.IO.File.Delete(fileName);

     }
  }

#2

Check the GridView1.SelectedRow is not null:

检查GridView1.SelectedRow不为null：

if (GridView1.SelectedRow == null) return;
string DeleteThis = GridView1.SelectedRow.Cells[0].Text;

#3

In my project i am using ajax and i create a web method in my code behind like this

在我的项目中我使用ajax并在我的代码中创建一个web方法，就像这样

in front

前面

 $("#attachedfiles a").live("click", function () {
            var row = $(this).closest("tr");
            var fileName = $("td", row).eq(0).html();
            $.ajax({
                type: "POST",
                url: "SendEmail.aspx/RemoveFile",
                data: '{fileName: "' + fileName + '" }',
                contentType: "application/json; charset=utf-8",
                dataType: "json",
                success: function () { },
                failure: function (response) {
                    alert(response.d);
                }
            });
            row.remove();
        });  

in code behind

在代码背后

        [WebMethod]
        public static void RemoveFile(string fileName)
        {
            List<HttpPostedFile> files = (List<HttpPostedFile>)HttpContext.Current.Session["Files"];
            files.RemoveAll(f => f.FileName.ToLower().EndsWith(fileName.ToLower()));

            if (System.IO.File.Exists(HttpContext.Current.Server.MapPath("~/Employee/uploads/" + fileName)))
            {
                System.IO.File.Delete(HttpContext.Current.Server.MapPath("~/Employee/uploads/" + fileName));
            }
        }

i think this will help you.

我想这会对你有所帮助。

#4

string sourceDir = @"c:\current";
string backupDir = @"c:\archives\2008";

try
{
    string[] picList = Directory.GetFiles(sourceDir, "*.jpg");
    string[] txtList = Directory.GetFiles(sourceDir, "*.txt");

    // Copy picture files. 
    foreach (string f in picList)
    {
        // Remove path from the file name. 
        string fName = f.Substring(sourceDir.Length + 1);

        // Use the Path.Combine method to safely append the file name to the path. 
        // Will overwrite if the destination file already exists.
        File.Copy(Path.Combine(sourceDir, fName), Path.Combine(backupDir, fName), true);
    }

    // Copy text files. 
    foreach (string f in txtList)
    {

        // Remove path from the file name. 
        string fName = f.Substring(sourceDir.Length + 1);

        try
        {
            // Will not overwrite if the destination file already exists.
            File.Copy(Path.Combine(sourceDir, fName), Path.Combine(backupDir, fName));
        }

        // Catch exception if the file was already copied. 
        catch (IOException copyError)
        {
            Console.WriteLine(copyError.Message);
        }
    }

    // Delete source files that were copied. 
    foreach (string f in txtList)
    {
        File.Delete(f);
    }
    foreach (string f in picList)
    {
        File.Delete(f);
    }
}

catch (DirectoryNotFoundException dirNotFound)
{
    Console.WriteLine(dirNotFound.Message);
}

#5

Delete any or specific file type(for example ".bak") from a path. See demo code below -

从路径中删除任何或特定的文件类型（例如“.bak”）。见下面的演示代码 -

class Program
        {
        static void Main(string[] args)
            {

            // Specify the starting folder on the command line, or in 
            TraverseTree(ConfigurationManager.AppSettings["folderPath"]);

            // Specify the starting folder on the command line, or in 
            // Visual Studio in the Project > Properties > Debug pane.
            //TraverseTree(args[0]);

            Console.WriteLine("Press any key");
            Console.ReadKey();
            }

        public static void TraverseTree(string root)
            {

            if (string.IsNullOrWhiteSpace(root))
                return;

            // Data structure to hold names of subfolders to be
            // examined for files.
            Stack<string> dirs = new Stack<string>(20);

            if (!System.IO.Directory.Exists(root))
                {
                return;
                }

            dirs.Push(root);

            while (dirs.Count > 0)
                {
                string currentDir = dirs.Pop();
                string[] subDirs;
                try
                    {
                    subDirs = System.IO.Directory.GetDirectories(currentDir);
                    }

                // An UnauthorizedAccessException exception will be thrown if we do not have
                // discovery permission on a folder or file. It may or may not be acceptable 
                // to ignore the exception and continue enumerating the remaining files and 
                // folders. It is also possible (but unlikely) that a DirectoryNotFound exception 
                // will be raised. This will happen if currentDir has been deleted by
                // another application or thread after our call to Directory.Exists. The 
                // choice of which exceptions to catch depends entirely on the specific task 
                // you are intending to perform and also on how much you know with certainty 
                // about the systems on which this code will run.
                catch (UnauthorizedAccessException e)
                    {
                    Console.WriteLine(e.Message);
                    continue;
                    }
                catch (System.IO.DirectoryNotFoundException e)
                    {
                    Console.WriteLine(e.Message);
                    continue;
                    }

                IEnumerable<FileInfo> files = null;
                try
                    {
                    //get only .bak file
                    var directory = new DirectoryInfo(currentDir);
                    DateTime date = DateTime.Now.AddDays(-15);
                    files = directory.GetFiles("*.bak").Where(file => file.CreationTime <= date);
                    }
                catch (UnauthorizedAccessException e)
                    {
                    Console.WriteLine(e.Message);
                    continue;
                    }
                catch (System.IO.DirectoryNotFoundException e)
                    {
                    Console.WriteLine(e.Message);
                    continue;
                    }

                // Perform the required action on each file here.
                // Modify this block to perform your required task.
                foreach (FileInfo file in files)
                    {
                    try
                        {
                        // Perform whatever action is required in your scenario.
                        file.Delete();
                        Console.WriteLine("{0}: {1}, {2} was successfully deleted.", file.Name, file.Length, file.CreationTime);
                        }
                    catch (System.IO.FileNotFoundException e)
                        {
                        // If file was deleted by a separate application
                        //  or thread since the call to TraverseTree()
                        // then just continue.
                        Console.WriteLine(e.Message);
                        continue;
                        }
                    }

                // Push the subdirectories onto the stack for traversal.
                // This could also be done before handing the files.
                foreach (string str in subDirs)
                    dirs.Push(str);
                }
            }
        }

for more reference - https://msdn.microsoft.com/en-us/library/bb513869.aspx

更多参考 - https://msdn.microsoft.com/en-us/library/bb513869.aspx