How to make the Default focus in content page from master page

Question

I have masterpage with content place holder. i have contentpage which is using master page . in all my content page i need to default focus on the text b

Answer 1

You could include this in your master page's load event:

// if the ID is constant you can use this:
/*TextBox textBox = (TextBox)Page.Controls[0]
                                .FindControl("ContentPlaceHolder1")
                                .FindControl("myTextBox");
*/

// this will look for the 1st textbox without hardcoding the ID
TextBox textBox = (TextBox)Page.Controls[0]
                            .FindControl("ContentPlaceHolder1")
                            .Controls.OfType()
                            .FirstOrDefault();

if (textBox != null)
{
    textBox.Focus();
}

This would match up with a content page that has the following markup:

EDIT: if LINQ isn't an option then you can use this instead:

foreach (Control control in Page.Controls[0].FindControl("ContentPlaceHolder1").Controls)
{
    if (control is TextBox)
    {
        ((TextBox)control).Focus();
        break;
    }
}