Introduction
Many people have asked me how I can pass a value from a child page to a parent page. In this article, I will show you how you can make some selections in the child page and pass those selections to the parent page.
Creating the Parent Page
Our parent page will consist of a button and a GridView control. The button will simply open a new window (child window). Let's see the code for the parent page:
protected void Page_Load(object sender, EventArgs e)
{
if (Session["SelectedItems"] != null)
{
GridView1.DataSource = (DataTable)Session["SelectedItems"];
GridView1.DataBind();
}
}
And to open the child window, write this code in the HTML view. The function OpenWindow is called when the button is clicked.
<input type="button" value="Open a new window"
onclick="OpenWindow()" id="Button1" />function OpenWindow()
{
window.open("NewWindow.aspx","MyWindow","height=450,width=300");
}
Okay, the above code will open a child window. Now let's see how the child window looks like:
Child Window
Our child window will contain a GridView control. The GridView control will also have checkboxes so you can select various rows. Once you click the button, the child window will close and you will see the selected items in the parent window.
Here is the button click event of the child page:
protected void Button1_Click(object sender, EventArgs e)
{
DataTable myTable = new DataTable();
myTable.Columns.Add("CategoryID");
myTable.Columns.Add("CategoryName");
DataRow myRow = null;
foreach (GridViewRow row in gvChild.Rows)
{
bool result = ((CheckBox) row.FindControl("CheckBox1")).Checked;
if (result)
{
myRow = myTable.NewRow();
myRow["CategoryID"] = row.Cells[0].Text;
myRow["CategoryName"] = row.Cells[1].Text;
myTable.Rows.Add(myRow);
}
}
Session["SelectedItems"] = myTable;
}
All I am doing is looping through the GridView and finding which rows are selected, and finally I put the items in the DataTable object. In the example above, I am using the row.Cells[0].Text property of the GridViewRow but you can easily use row.FindControl("Id of the control"). The good thing about the FindControl method is that if you later change the position of the columns, you don't need to change anything in the code.
Once, you get the selected items in the DataTable object, simply place them in the session variable. Now the only task left to do is to make a postback on the parent window and close the child window on the button click.
Here is the code that will do the trick (this code is for the child window):
<body onunload="PassValues()">
<script language="javascript" type="text/javascript">
function PassValues()
{
window.opener.document.forms(0).submit();
self.close();
}
</script>
Yup that's it!
