Javascript未在C＃代码中触发

Question

I have the following code to upload the attachment in a program. In the process, if the client choose same named document in the upload file which is previously upload in the program then the client must be given alert message to change the name of the document.

Code Snippet:

private string UploadFile()
    {
        string pathToSaveFile = Server.MapPath("~/Data/");
        string clientFileName = System.IO.Path.GetFileName(FileUpload1.PostedFile.FileName);

        string upload_data = pathToSaveFile + clientFileName;

        if (FileUpload1.PostedFile != null && FileUpload1.PostedFile.ContentLength > 0)
        {

            if (System.IO.File.Exists(upload_data))
            {
                //using Response.write
                Response.Write(@"<script type='text/javascript'>alert('Rename it please.');</script>");

                //ClientScriptManager
                var clientScript = Page.ClientScript;
                clientScript.RegisterClientScriptBlock(this.GetType(), "AlertScript", "alert('Rename it please.')'", true);

                //ScriptManger
                ScriptManager.RegisterClientScriptBlock(this.Page, this.Page.GetType(), "alert", "alert('Member Registered Sucessfully');", true);

            }
            else
            {
                FileUpload1.PostedFile.SaveAs(System.IO.Path.Combine(pathToSaveFile, clientFileName));
            }
        }
        else
        {
            Response.Write("Not Available");
        }

        return clientFileName;
    }

I have used the types of javascript codes in the program but they all doesn't work. The code reader just reads the code and passes through it.

As I submit the form b utton, all the forms fields are read and kept in an object and when it comes to an upload part the above code is read and the clientFileName is passed to the filename object and passed to the sqlquery to enter it into the database.

It doesn't show any alert popup for the client to change the name of the file. So the samefile name is passed to the server and conflict starts because of the same name.

Thanks.

Answer 1

The alert pop up only when you re-posting the website. It cannot work inside the C# code.

See the code below(reference only):

private bool UploadFile()
{
    string pathToSaveFile = Server.MapPath("~/Data/");
    string clientFileName = System.IO.Path.GetFileName(FileUpload1.PostedFile.FileName);

    string upload_data = pathToSaveFile + clientFileName;

    if (FileUpload1.PostedFile != null && FileUpload1.PostedFile.ContentLength > 0)
    {

        if (System.IO.File.Exists(upload_data))
        {
            //using Response.write
            Response.Write(@"<script type='text/javascript'>alert('Rename it please.');</script>");

            //ClientScriptManager
            var clientScript = Page.ClientScript;
            clientScript.RegisterClientScriptBlock(this.GetType(), "AlertScript", "alert('Rename it please.')'", true);

            //ScriptManger
            ScriptManager.RegisterClientScriptBlock(this.Page, this.Page.GetType(), "alert", "alert('Member Registered Sucessfully');", true);
    return false;
        }
        else
        {
            FileUpload1.PostedFile.SaveAs(System.IO.Path.Combine(pathToSaveFile, clientFileName));
        }
    }
    else
    {
        Response.Write("Not Available");
    }

ViewState["FileName"] = clientFileName;
    return true;
}

Outside the function use something like this:

if(UploadFile())
        //run your SQL queue
    else
        return;//do all the return that will repost the website.