How to maintain file upload values in session while editing and updating Gridview

Question

I have developed and discussed a lot about the file upload and we were maintaining the upload file in session and data table

I used session for time being for gridview footer and emptydata template.

i want the same logic have to be implement for gridview editing and updating.

Below is my code and it is working for Footer Template and empty data template and tell me what properties I need to use to get the find gridvie control as discussed below...

My question is, How to retain the file upload values into session variable in gridview edit an update when i select dropdown values in gridview....?

Note : i am planning to use data table for maintaining file upload values in gridview and this is already in process (already posted and got reply for that). for the short demo to end user, i have to use session..

 
     
           
                
                      
                      
 	            
          
     	
              
     	
     


 
                                
                                    File Upload

if (!IsPostBack)
 { 
      FileUpload fuUpload = null;
                        if (gvcustomer.FooterRow != null)
                        {
                            control = gvcustomer.FooterRow;                            
			    DropDownList1 = (control.FindControl("ddlcity") as DropDownList);
                        }
                        else
                        {
                            control = gvcustomer.Controls[0].Controls[0];
                            DropDownList1 = (control.FindControl("ddlcity") as DropDownList);
                        }
                        fuUpload = (FileUpload)control.FindControl("fuUpload");
                        fuUpload.Attributes["onchange"] = "UploadFile(this)";
 
}
if (this.IsPostBack)
            {
                if (gvcustomer.FooterRow != null)
                {
                    control = gvcustomer.FooterRow;
                }
                else
                {
                    control = gvcustomer.Controls[0].Controls[0];
                }
                Label label = (control.FindControl("ImageErrorLabel") as Label);
                FileUpload fuUpload = (FileUpload)control.FindControl("fuUpload");
                if (Session["FileUpload1"] == null && fuUpload.HasFile)
                {
                    Session["FileUpload1"] = fuUpload.PostedFile;
                    label.Text = Path.GetFileName(fuUpload.PostedFile.FileName);
                }
                else if (Session["FileUpload1"] != null && (!fuUpload.HasFile))
                {
                    HttpPostedFile file = (HttpPostedFile)Session["FileUpload1"];
                    label.Text = Path.GetFileName(file.FileName);
                }
                else if (fuUpload.HasFile)
                {
                    Session["FileUpload1"] = fuUpload.PostedFile;
                    label.Text = Path.GetFileName(fuUpload.PostedFile.FileName);
                }
            }

Accepted Answer

Hi @Gani_tpt,

The edit row cannot be obtained directly. Perhaps you can try to record EditIndex through Session and assign a value in OnRowDataBound.

Session["EditIndex"] = gvCustomers.EditIndex;

protected void OnRowDataBound(object sender, GridViewRowEventArgs e)
{           
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
        if ((e.Row.RowState & DataControlRowState.Edit) > 0)
        {
            DropDownList DropDownList1 = (e.Row.FindControl("ddlCustomers") as DropDownList);
            List items = new List();
            items.Add(new Item() { Value = "1", Text = "USA" });
            items.Add(new Item() { Value = "2", Text = "UK" });
            items.Add(new Item() { Value = "3", Text = "AUS" });
            items.Add(new Item() { Value = "4", Text = "OTHERS" });
            DropDownList1.DataSource = items;
            DropDownList1.DataTextField = "Text";
            DropDownList1.DataValueField = "Value";
            DropDownList1.DataBind();
            DropDownList1.Items.Insert(0, new ListItem("--Select --", "0"));
            DataRowView dr = e.Row.DataItem as DataRowView;
            ////ddList.SelectedItem.Text = dr["category_name"].ToString();
            //ddList.SelectedValue = dr["category_name"].ToString();
            FileUpload fuUpload = (FileUpload)e.Row.FindControl("fuUpload");
            fuUpload.Attributes["onchange"] = "UploadFile(this)";
            Label label = (e.Row.FindControl("ImageErrorLabel") as Label);
            if (Session["FileUpload1"] != null)
            {
                HttpPostedFile file = (HttpPostedFile)Session["FileUpload1"];
                label.Text = Path.GetFileName(file.FileName);
            }
            Session["EditIndex"] = gvCustomers.EditIndex;
        }
    }
}

Control control = null;
if (gvCustomers.FooterRow != null && (Convert.ToInt32(Session["EditIndex"]) < 0 || Session["EditIndex"] == null))
{
    control = gvCustomers.FooterRow;
}
else if (Session["EditIndex"] != null && Convert.ToInt32(Session["EditIndex"]) >= 0)
{
    control = gvCustomers.Rows[Convert.ToInt32(Session["EditIndex"])];
}
else
{
    control = gvCustomers.Controls[0].Controls[0];
}

All test code:



    
    
    
    


    
        
        
            
                
                    
                        
                        
                        
                    
                    
                        
                        
                        
                    
                
                
                    
                        <%# Eval("Name") %>
                    
                    
                        
                    
                    
                        
                    
                
                
                    
                        <%# Eval("Country") %>
                    
                    
                        
                    
                    
                        
                    
                
                
                    
                    
                    
                        
                            
                            
                            
                        
                    
                    
                        
                        
                        
                    
                
                
                    
                        <%# Eval("FileName") %>
                    
                    
                        
                        
                        
                    
                    
                        
                        
                        
                    
                
                
            
            
                
                    Customer Name
                    Name
                    Country
                    DOB
                    Upload

 protected void Page_Load(object sender, EventArgs e)
 {
     Control control = null;
     if (!this.IsPostBack)
     {
         this.BindGrid();
         if (gvCustomers.FooterRow != null && (Convert.ToInt32(Session["EditIndex"]) < 0 || Session["EditIndex"] == null))
         {
             control = gvCustomers.FooterRow;
         }
         else if (Session["EditIndex"] != null && Convert.ToInt32(Session["EditIndex"]) >= 0)
         {
             control = gvCustomers.Rows[Convert.ToInt32(Session["EditIndex"])];
         }
         else
         {
             control = gvCustomers.Controls[0].Controls[0];
         }
         TextBox txtDOB = control.FindControl("txtDOB") as TextBox;
         txtDOB.Attributes.Add("readonly", "readonly");
         FileUpload fuUpload = (FileUpload)control.FindControl("fuUpload");
         fuUpload.Attributes["onchange"] = "UploadFile(this)";
         DropDownList DropDownList1 = (control.FindControl("ddlCustomers") as DropDownList);
         List items = new List();
         items.Add(new Item() { Value = "1", Text = "USA" });
         items.Add(new Item() { Value = "2", Text = "UK" });
         items.Add(new Item() { Value = "3", Text = "AUS" });
         items.Add(new Item() { Value = "4", Text = "OTHERS" });
         DropDownList1.DataSource = items;
         DropDownList1.DataTextField = "Text";
         DropDownList1.DataValueField = "Value";
         DropDownList1.DataBind();
         DropDownList1.Items.Insert(0, new ListItem("--Select --", "0"));
     }
     if (this.IsPostBack)
     {
         if (gvCustomers.FooterRow != null && (Convert.ToInt32(Session["EditIndex"]) < 0 || Session["EditIndex"] == null))
         {
             control = gvCustomers.FooterRow;
         }
         else if (Session["EditIndex"] != null && Convert.ToInt32(Session["EditIndex"]) >= 0)
         {
             control = gvCustomers.Rows[Convert.ToInt32(Session["EditIndex"])];
         }
         else
         {
             control = gvCustomers.Controls[0].Controls[0];
         }
         Label label = (control.FindControl("ImageErrorLabel") as Label);
         FileUpload fuUpload = (FileUpload)control.FindControl("fuUpload");
         if (Session["FileUpload1"] == null && fuUpload.HasFile)
         {
             Session["FileUpload1"] = fuUpload.PostedFile;
             label.Text = Path.GetFileName(fuUpload.PostedFile.FileName);
         }
         else if (Session["FileUpload1"] != null && (fuUpload.PostedFile.ContentLength < 0))
         {
             HttpPostedFile file = (HttpPostedFile)Session["FileUpload1"];
             label.Text = Path.GetFileName(file.FileName);
         }
         else if (fuUpload.HasFile)
         {
             Session["FileUpload1"] = fuUpload.PostedFile;
             label.Text = Path.GetFileName(fuUpload.PostedFile.FileName);
         }               
     }
 }
 protected void OnRowEditing(object sender, GridViewEditEventArgs e)
 {
     gvCustomers.EditIndex = e.NewEditIndex;
     this.BindGrid();
 }
 protected void OnRowDataBound(object sender, GridViewRowEventArgs e)
 {           
     if (e.Row.RowType == DataControlRowType.DataRow)
     {
         if ((e.Row.RowState & DataControlRowState.Edit) > 0)
         {
             DropDownList DropDownList1 = (e.Row.FindControl("ddlCustomers") as DropDownList);
             List items = new List();
             items.Add(new Item() { Value = "1", Text = "USA" });
             items.Add(new Item() { Value = "2", Text = "UK" });
             items.Add(new Item() { Value = "3", Text = "AUS" });
             items.Add(new Item() { Value = "4", Text = "OTHERS" });
             DropDownList1.DataSource = items;
             DropDownList1.DataTextField = "Text";
             DropDownList1.DataValueField = "Value";
             DropDownList1.DataBind();
             DropDownList1.Items.Insert(0, new ListItem("--Select --", "0"));
             DataRowView dr = e.Row.DataItem as DataRowView;
             ////ddList.SelectedItem.Text = dr["category_name"].ToString();
             //ddList.SelectedValue = dr["category_name"].ToString();
             FileUpload fuUpload = (FileUpload)e.Row.FindControl("fuUpload");
             fuUpload.Attributes["onchange"] = "UploadFile(this)";
             Label label = (e.Row.FindControl("ImageErrorLabel") as Label);
             if (Session["FileUpload1"] != null)
             {
                 HttpPostedFile file = (HttpPostedFile)Session["FileUpload1"];
                 label.Text = Path.GetFileName(file.FileName);
             }
             Session["EditIndex"] = gvCustomers.EditIndex;
         }
     }
 }
 protected void OnRowUpdating(object sender, GridViewUpdateEventArgs e)
 {
     gvCustomers.EditIndex = -1;
     this.BindGrid();
 }
 protected void OnRowCancelingEdit(object sender, EventArgs e)
 {
     gvCustomers.EditIndex = -1;
     this.BindGrid();
 }
 protected void OnRowDeleting(object sender, GridViewDeleteEventArgs e)
 {
 }
 protected void Upload(object sender, EventArgs e)
 {
     Control control = null;
     if (gvCustomers.FooterRow != null && (Convert.ToInt32(Session["EditIndex"]) < 0 || Session["EditIndex"] == null))
     {
         control = gvCustomers.FooterRow;
     }
     else if (Session["EditIndex"] != null && Convert.ToInt32(Session["EditIndex"]) >= 0)
     {
         control = gvCustomers.Rows[Convert.ToInt32(Session["EditIndex"])];
     }
     else
     {
         control = gvCustomers.Controls[0].Controls[0];
     }
     Label label = (control.FindControl("ImageErrorLabel") as Label);
     FileUpload fuUpload = (FileUpload)control.FindControl("fuUpload");
     if (Session["FileUpload1"] == null && fuUpload.HasFile)
     {
         Session["FileUpload1"] = fuUpload.PostedFile;
         label.Text = Path.GetFileName(fuUpload.PostedFile.FileName);
         HttpPostedFile file = (HttpPostedFile)Session["FileUpload1"];
         SaveFile(file);
     }
     else if (Session["FileUpload1"] != null && (fuUpload.PostedFile.ContentLength <0))
     {
         HttpPostedFile file = (HttpPostedFile)Session["FileUpload1"];
         label.Text = Path.GetFileName(file.FileName);
         SaveFile(file);
     }
     else if (fuUpload.HasFile)
     {
         Session["FileUpload1"] = fuUpload.PostedFile;
         label.Text = Path.GetFileName(fuUpload.PostedFile.FileName);
         SaveFile(fuUpload.PostedFile);
     }
 }
 private void SaveFile(HttpPostedFile file)
 {
     string fname = Path.GetFileName(file.FileName);
     file.SaveAs(Server.MapPath("~/images/" + fname));
 }
 private void BindGrid()
 {
     string constr = ConfigurationManager.ConnectionStrings["ConString"].ConnectionString;
     string query = "SELECT Name, Country,FileName FROM Customers";
     using (SqlConnection con = new SqlConnection(constr))
     {
         using (SqlCommand cmd = new SqlCommand(query, con))
         {
             using (SqlDataAdapter sda = new SqlDataAdapter(cmd))
             {
                 using (DataTable dt = new DataTable())
                 {
                     sda.Fill(dt);
                     con.Open();
                     gvCustomers.DataSource = dt;
                     gvCustomers.DataBind();
                     con.Close();
                 }
             }
         }
     }
 }
 protected void ddlCustomers_SelectedIndexChanged(object sender, EventArgs e)
 {
     Control control = null;
     if (gvCustomers.FooterRow != null && (Convert.ToInt32(Session["EditIndex"]) < 0 || Session["EditIndex"] == null))
     {
         control = gvCustomers.FooterRow;
     }
     else if (Session["EditIndex"] != null && Convert.ToInt32(Session["EditIndex"]) >= 0)
     {
         control = gvCustomers.Rows[Convert.ToInt32(Session["EditIndex"])];
     }
     else
     {
         control = gvCustomers.Controls[0].Controls[0];
     }
     DropDownList ddlCustomers = (control.FindControl("ddlCustomers") as DropDownList);
     TextBox txtOtherCustomers = control.FindControl("txtOtherCustomers") as TextBox;
     if (ddlCustomers.SelectedItem.Text == "OTHERS")
     {
         txtOtherCustomers.Visible = true;
     }
     else
     {
         txtOtherCustomers.Visible = false;
     }
 }
 public class Item
 {
     public Item() { }
     public string Value { set; get; }
     public string Text { set; get; }
 }
 protected void Add(object sender, EventArgs e)
 {
     Control control = null;
     if (gvCustomers.FooterRow != null)
     {
         control = gvCustomers.FooterRow;
     }
     else if (gvCustomers.EditIndex >= 0)
     {
         control = gvCustomers.Rows[gvCustomers.EditIndex];
     }
     else
     {
         control = gvCustomers.Controls[0].Controls[0];
     }
     string name = (control.FindControl("txtName") as TextBox).Text;
     string country = (control.FindControl("txtCountry") as TextBox).Text;
     string txtDOB = (control.FindControl("txtDOB") as TextBox).Text;
     HttpPostedFile file = (HttpPostedFile)Session["FileUpload1"];
     string filename = Path.GetFileName(file.FileName);
     byte[] bytes = null;
     if (file != null)
     {
         BinaryReader br = new BinaryReader(file.InputStream);
         bytes = br.ReadBytes((int)file.InputStream.Length);
     }
     string constr = ConfigurationManager.ConnectionStrings["ConString"].ConnectionString;
     string query = "INSERT INTO Customers VALUES(@Name, @Country,@FileName,@Data,@Data1)";
     using (SqlConnection con = new SqlConnection(constr))
     {
         using (SqlCommand cmd = new SqlCommand(query, con))
         {
             cmd.Parameters.AddWithValue("@Name", name);
             cmd.Parameters.AddWithValue("@Country", country);
             cmd.Parameters.AddWithValue("@FileName", filename);
             cmd.Parameters.AddWithValue("@Data", bytes);
             cmd.Parameters.AddWithValue("@Data1", bytes);
             con.Open();
             cmd.ExecuteNonQuery();
             con.Close();
         }
     }
     Response.Redirect(Request.Url.AbsoluteUri);
 }

Best regards,
Lan Huang

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Answer

The FileUpload buffer is destroyed when the request ends which includes the HttpPostedFile. In other words, the HttpPostedFile stream cannot persist between post backs due to fundamentally how the Server Control works. It seems like you are not testing the code.

As suggested in your previous thread(s), read the file stream into a byte array. The byte array can be stored in Session and persist between post back.

protected void Submit_Click(object sender, EventArgs e)
{            
    Stream myStream = MyFile.FileContent;
    Byte[] buff = new Byte[MyFile.PostedFile.ContentLength];
    myStream.Read(buff, 0, MyFile.PostedFile.ContentLength);
    Session["FileBuffer"] = buff;
    Session["FileName"] = MyFile.FileName;
}
protected void TestSession_Click(object sender, EventArgs e)
{
    Byte[] buff = (byte[])Session["FileBuffer"];
    string fileName = (string)Session["FileName"];
    string filePath = Server.MapPath($"~/images/{fileName}") ;
    using (var fs = new FileStream(filePath, FileMode.Create, FileAccess.Write))
    {
        fs.Write(buff, 0, buff.Length);
    }
}

Keep in mind, Session will not work if the web application is load balanced.

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How to maintain file upload values in session while editing and updating Gridview

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