How to implement add & remove recipients from Asp.Net GridView to TextBox using CheckBox

Question

I'm stuck into this problem where on a web application , I'm uploading contacts and retrieving them into a GridView . I'm using CheckBoxes to select or deselect the mobile numbers from the Gridview and storing the selected numbers into a multiline TextBox separated with commas "," to send multiple SMS . Now, the problem is that I'm not able to remove the added numbers or string from the TextBox when I'm unchecking the CheckBoxes in the GridView . Please help me through this problem. It's eating my time up!! Thanks in advance..
Below is my code:

protected void chkboxSelectAll_CheckedChanged(object sender, EventArgs e)
{
    bool SomethingChecked = false;
    CheckBox ChkBoxHeader = (CheckBox)gvcntct.HeaderRow.FindControl("chkboxSelectAll");
    foreach (GridViewRow row in gvcntct.Rows)
    {
        CheckBox ChkBoxRows = (CheckBox)row.FindControl("chkEmp");
        if (ChkBoxHeader.Checked == true)
        {
            ChkBoxRows.Checked = true;
        }
        else
        {
            ChkBoxRows.Checked = false;
            TextBox2.Text = "";
        }            
    }
    if (!SomethingChecked)
    {
        TextBox2.Text = "";
    }            
}

Answer 1

You can remove the unchecked ID text from the TextBox2 by using:

TextBox2.Text.Replace(string.Format(", {0}", ID), "");

Here's the complete code (Note I reomved some unnecessary code your'e using, like the 3rd else statement which can never be reached, since a checkbox is either true or false ):

protected void chkboxSelectAll_CheckedChanged(object sender, EventArgs e)
{
    TextBox2.Text = ""
    CheckBox ChkBoxHeader = (CheckBox)gvcntct.HeaderRow.FindControl("chkboxSelectAll");
    foreach (GridViewRow row in gvcntct.Rows)
    {
        CheckBox ChkBoxRows = (CheckBox)row.FindControl("chkEmp");
        ChkBoxRows.Checked = ChkBoxHeader.Checked;        
    }
}

protected void chkEmp_CheckedChanged(object sender, EventArgs e)
{
    System.Web.UI.WebControls.CheckBox CheckBox1 = (System.Web.UI.WebControls.CheckBox)sender;
    GridViewRow row = (GridViewRow)CheckBox1.NamingContainer;
    Label lblUser = (Label)row.FindControl("lblMake");
    string ID = row.Cells[2].Text;

    if (TextBox2.Text.Length > 0)
    {
        string[] Ids = TextBox2.Text.Split(',');

        if (CheckBox1.Checked == true)
        {
            TextBox2.Text += string.Format(", {0}", ID);
        }
        else if (CheckBox1.Checked == false)
        {
            CheckBox ChkBoxHeader = (CheckBox)gvcntct.HeaderRow.FindControl("chkboxSelectAll");
            foreach (GridViewRow rows in gvcntct.Rows)
            {
                CheckBox ChkBoxRows = (CheckBox)rows.FindControl("chkEmp");
                ChkBoxHeader.Checked = false;
                ChkBoxRows.Checked = false;
                TextBox2.Text = TextBox2.Text
                                   .Replace(string.Format(", {0}", ID), "")
                                   .Replace(string.Format("{0}", ID), "");
            }
        }
        else
        {
            TextBox2.Text = string.Empty;
            int index = 0;
            foreach (string s in Ids)
            {
                if (!s.Equals(","))
                {
                    TextBox2.Text += string.Format("{0},", Ids[index]);
                }

                index++;
            }
            if (TextBox2.Text.Contains(","))
            {
                TextBox2.Text = TextBox2.Text.Replace(string.Format(", {0}", ID), "");
            }
        }
    }
    else
    {
        TextBox2.Text = ID;
    }
}