In my previous post here, I wrote an example that demonstrates how are we going to generate table rows dynamically using ASP Table on click of
the Button control. Now based on some comments in my previous example and in
the forums they wanted to implement it within Masterpage. Unfortunately
the code in my previous example doesn't work in Masterpage for
the following main reasons:
The Table is dynamically added within
the Form tag and so
the TextBox control will not be generated correcty in
the page.
The data will not be retained on each and every postbacks because
the SetPreviousData() method is looking for
the Table element within
the Page and not on
the MasterPage.
The Request.Form key value should be set correctly since all controls within
the master page are prefixed with
the naming containter ID to prevent duplicate ids on
the final rendered HTML. For example
the TextBox control with
the ID of TextBoxRow will turn to ID to this ctl00$MainBody$TextBoxRow. In order for
the previous example to work within Masterpage then we will have to correct those three main reasons
above and this post will guide you how to correct it. Suppose we have this content page declaration below: <asp:Content ID="Content1" ContentPlaceHolderID="MainHead" Runat="Server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="MainBody" Runat="Server">
<asp:PlaceHolder ID="PlaceHolder1" runat="server">
<asp:Button ID="BTNAdd" runat="server" Text="Add New Row" OnClick="BTNAdd_Click" />
</asp:PlaceHolder>
</asp:Content>
As you notice I've added a PlaceHolder control within
the MainBody ContentPlaceHolder. This is because we are going to generate
the Table in
the PlaceHolder instead of generating it within
the Form element. Now since issue #1 is already corrected then let's proceed to
the code beind part. Here are
the full code blocks below:
using System;
using System.Web.UI;
using System.Web.UI.WebControls;
public partial class DynamicControlDemo : System.Web.UI.Page
{
private int numOfRows = 1;
protected void Page_Load(object sender, EventArgs e) {
//Generate
the Rows on Initial Load
if (!Page.IsPostBack) {
GenerateTable(numOfRows);
}
}
protected void BTNAdd_Click(object sender, EventArgs e) {
if (ViewState["RowsCount"] != null) {
numOfRows = Convert.ToInt32(ViewState["RowsCount"].ToString());
GenerateTable(numOfRows);
}
}
private void SetPreviousData(int rowsCount, int colsCount) {
Table table = (Table)this.Page.Master.FindControl("MainBody").FindControl("Table1"); // **** if (table != null) {
for (int i = 0; i < rowsCount; i++) {
for (int j = 0; j < colsCount; j++) {
//Extracting
the Dynamic Controls from
the Table
TextBox tb = (TextBox)table.Rows[i].Cells[j].FindControl("TextBoxRow_" + i + "Col_" + j);
//Use Request object for getting
the previous data of
the dynamic textbox
tb.Text = Request.Form["ctl00$MainBody$TextBoxRow_" + i + "Col_" + j];//***** }
}
}
}
private void GenerateTable(int rowsCount) {
//Creat
the Table and Add it to
the Page
Table table = new Table();
table.ID = "Table1";
PlaceHolder1.Controls.Add(table);//****** //The number of Columns to be generated
const int colsCount = 3;//You can changed
the value of 3 based on you requirements
// Now iterate through
the table and add your controls
for (int i = 0; i < rowsCount; i++) {
TableRow row = new TableRow();
for (int j = 0; j < colsCount; j++) {
TableCell cell = new TableCell();
TextBox tb = new TextBox();
// Set a unique ID for each TextBox added
tb.ID = "TextBoxRow_" + i + "Col_" + j;
// Add
the control to
the TableCell
cell.Controls.Add(tb);
// Add
the TableCell to
the TableRow
row.Cells.Add(cell);
}
// And finally, add
the TableRow to
the Table
table.Rows.Add(row);
}
//Set Previous Data on PostBacks
SetPreviousData(rowsCount, colsCount);
//Sore
the current Rows Count in ViewState
rowsCount++;
ViewState["RowsCount"] = rowsCount;
}
}
As you observed
the code is pretty much similar to
the previous example except for
the highlighted lines
above.
That's it! I hope someone find this post usefu!
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