How to get values of CheckBoxes inside a gridview that are checked using asp .net

Question

I am using checkbox in gridview .... I am using it in 1st cell.... When I select the checkbox at run time, I need to get those values... but on selecting or on click to checkbox, it's not finding or value is taking as FALSE... how to write in asp.net backend and in c# code?

 <asp:TemplateField>
   <ItemTemplate >
       <asp:checkbox id="ShowAddress" runat="server" />
  </ItemTemplate>
 </asp:TemplateField>

Code-behind:

  protected void Button1_Click(object sender, EventArgs e)
    {
        // Looping through all the rows in the GridView

        foreach (GridViewRow di in GridView1.Rows)
        {
         CheckBox chkBx = (CheckBox)di.FindControl("ShowAddress");

            if (chkBx != null && chkBx.Checked)
            {
                /// put your code here
            }
        }
    }

Is there any implementation to be done in script at page load?

Can anyone help?

Answer 1

StringCollection idCollection = new StringCollection();
string strID = string.Empty;

for (int i = 0; i < GridView1.Rows.Count; i++)
{
   CheckBox chkDelete = (CheckBox) GridView1.Rows.Cells[0].FindControl("chkSelect");
   if (chkDelete != null)
   {
     if (chkDelete.Checked)
      {
          strID = GridView1.Rows.Cells[1].Text;
         idCollection.Add(strID);
    }
  }
} 

for more details check this link: http://www.itworld2.com/ghowto.aspx?id=69

Answer 2

How do you populate your GridView? If you do this in Page_Load, make sure you are not doing it on postbacks (check IsPostBack).

Is your chkBx variable null?

The following code works:

    protected void Button1_Click(object sender, EventArgs e)
    {
        foreach (GridViewRow row in GridView1.Rows)
        {
            CheckBox chk = row.Cells[0].Controls[0] as CheckBox;
            if (chk != null && chk.Checked)
            {
                // ...
            }
        }
    }

Answer 3

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
     Loadgridview();// its a correct
    }//            not Loadgridview() here if you load above error is occur
 }

check it

Answer 4

int i = 0;
foreach (GridViewRow row in GridView1.Rows)
{
    CheckBox chk = (CheckBox)GridView_AdminTags.Rows[i].Cells[0].FindControl("chkTag");
    if (chk != null)
        if (chk.Checked)
        {
            ////.......;
        }
    i++;
}
i = 0;

Answer 5

Jakob Answer will work if below line is used. Even one control only in the cell, index need to be 1 not 0

CheckBox chk = row.Cells[0].Controls[1] as CheckBox;

Thank you Sam