使图像路径唯一

Question

I have an ASP.NET (4.5) website.

This button command below that inserts employeename, employeelastname, employeephoto to images folder and imagepath to db.

I want that the imagepath to be automatically uniquename + extension;

string filepath = //"uniquename" + ext;

so that, EmployeeID is unique so there is no confusion or duplicate photos.

How can I achieve that?

Thank you.

protected void Button1_Click(object sender, EventArgs e) //Insert
    {

    if (FileUploadControl.HasFile)
            {
                string ext = Path.GetExtension(FileUploadControl.FileName);

                if (ext == ".jpg" || ext == ".png" || ext == ".jpeg" || ext == ".gif")
                {
                    try
                    {
                        cnn.Open();


                        SqlCommand cmd = new SqlCommand("INSERT INTO Employees (EmployeeFirstName, EmployeeLastName, EmployeePhotoPath) VALUES (@item1,@item2,@img)", cnn);
                        cmd.Parameters.AddWithValue("@item1", TextBox1.Text);
                        cmd.Parameters.AddWithValue("@item2", TextBox2.Text);

                        string filepath = //"uniquename" + ext;
                        FileUploadControl.SaveAs(Server.MapPath("Images/") + filepath);
                        cmd.Parameters.AddWithValue("@img", filepath);

                        cmd.ExecuteNonQuery();

                        cnn.Close();
                        Label3.Text = "successfully inserted";
                    }

                    catch (Exception ex)
                    {
                        Label3.Text = ex.Message;
                    }

                    temizle();
                }

                else
                {
                    Label3.Text = "selected file is not a photo";
                }
            }
            else
            {
                Label3.Text = "please upload employee photo";
            }
        }
   }

Answer 1

If all you need is for the file names to be unique and you don't necessarily care about their names, a simple solution would be to use a guid for the file name:

string filepath = Guid.NewGuid().ToString() + ext;

It would probably also be a good idea to add the employee name to the filename so it will be easier to identify the files just by looking at their names:

string filepath = string.Format("{0}-{1}-{2}{3}",
                                TextBox1.Text,
                                TextBox2.Text,
                                Guid.NewGuid().ToString(),
                                ext);

Answer 2

Another option, if you don't want to do the INSERT and SCOPE_IDENTITY route is to use a GUID .

Trying to build your own unique IDs (like through a combination of names + times or anything else you can think up) is more likely to produce a duplicate than a GUID.

string filepath = Guid.NewGuid().ToString() + ext;

Answer 3

I will start creating a stored procedure to delegate the job to add the record in the database figuring out the name of the file. The stored procedure returns the new ID and you can catch it outside as a scalar value

CREATE PROCEDURE EmployeeAdd
(
   @firstN nvarchar(50),
   @lastN nvarchar(50),
   @ext nvarchar(10)
)
as
BEGIN
     DECLARE @newID int
     INSERT INTO Employees (EmployeeFirstName, EmployeeLastName, EmployeePhotoPath) 
                 VALUES (@firstN, @lastN, '')
     SET @newID = SCOPE_IDENTITY()
     DECLARE @newPath nvarchar(30)
     SET @newPath = CONVERT(nvarchar(10), @newID) + '.' + @ext
     UPDATE Employees SET EmployeePhotoPath = @newPath WHERE EmployeeID = @newID
     SELECT @newID
END

......    
SqlCommand cmd = new SqlCommand("EmployeeAdd", cnn);
cmd.Parameters.AddWithValue("@firstN", TextBox1.Text);
cmd.Parameters.AddWithValue("@lastN", TextBox2.Text);
cmd.Parameters.AddWithValue("@ext", ext);
int result = Convert.ToInt32(cmd.ExecuteScalar());
FileUploadControl.SaveAs(Server.MapPath("Images/") + string.Format("{0}.{1}", result, ext));
....

Can't test all just now, but I think that the idea is clear.