Question

I have a database that holds users documents. The Users can store their own meta-data to each document and to accomedate this I have 20 “Key” fields. Each user can use 1 to 20 columns and rename them and order them in the gridview as they please.

The document table looks like this

Documents:
ID int primary key identity,
SiteID int foreign key references sites(id),
PDFFolder varchar(100),
Key1 varchar(300),
keyN varchar(300);  //Upto 20 keys

Now I have another table called KeyNames:

KeyNames:
ID int primary key identity,
SiteId int foriegn key references sites(id),
KeyName1 varchar(50),
KeyOrder1 int,         //1 is Textbox, 2 is Multi Choice, 3 is date ect
KeyType1 int,
KeyNameN varchar(50),   //Repeat 20times
KeyOrderN int,
KeyTypeN int

The Current method I am using is to get a DataTable of the documents for a certain user (who owns a site)

DataTable documents = GetDocuments(int userId, int siteId);

Then I change the Order and the Heading of each Key, If the order < 0 then its removed

   //Set Order of Keys
    if ((keys.KeyOrder1 <0) || (keys.KeyOrder1 == null))
    { 
        documentsTable.Columns.Remove("Key1");
   }
   else
    {
        documentsTable.Columns["Key1"].SetOrdinal((int)keys.KeyOrder1);
        documentsTable.Columns["Key1"].ColumnName = keys.Keyname1;                
    }

    //Repeat 20 times

now I simply set the datasource of my gridview to the DataTable and Bind

this.Session["documents"] = documentsTable; //Save to session for future use
gvMail.DataSource = documentsTable;
gvMail.DataBind();

All works well except now I need to make it so the user can edit each Key and save it back to the database. To make things harder, when each row is put in editview I want it to be either a Textbox or DropDownView (in future ill use JavaScript to make a date picker, but not for this example).

I have tried to reverse the process

 protected void btnEdit_Click(Object sender, EventArgs e)
 {
        Button btn = sender as Button;
        GridViewRow row = (GridViewRow)btn.NamingContainer;

        if (btn.Text == "Edit")
        {
            for (int i = 0; i < row.Cells.Count; i++)
            {
               //Get Header
               string header = gvMail.HeaderRow.Cells[i].Text;
               //Get Keys
               KeyName keys = db.GetKeys(SiteID);
               //Cycle through keys to find right key 
               //ie if (keys.KeyName1 == header)
               //  {
               //    switch (keys.KeyType1)
                     {
                        case 1: //Add Textbox
                        case 2: //add drop down box code
               //  }
        }

A couple of the many problem I have is it requires i repeat code 20 times to cycle through all the keys to find which key it is and find the type.

Then the next problem is when I add a control by:

                    TextBox txtBox = new TextBox();
                    txtBox.Text = row.Cells[i].Text;

                    row.Cells[i].Controls.Add(txtBox);

it does not exist after the postback..

Answer 1

Why don’t you use Template Columns in DataGridView to create TextBox and DropDown list columns? It’s very simple and easy and will solve your issue to clearing controls after postback.