How To Enable and Disable Textbox On CheckBox Check change in GridView using javascript

Giving you a ready sample. Say below is your grid view

<asp:GridView ID="gvM" runat="server">
        <Columns>
            <asp:TemplateField>
                <ItemTemplate>
                    <asp:CheckBox runat="server" ID="chkIs" onclick="GetCheckStatus()"></asp:CheckBox>
                </ItemTemplate>
            </asp:TemplateField>
            <asp:TemplateField>
                <ItemTemplate>
                    <asp:TextBox runat="server" ID="txtId"></asp:TextBox>
                </ItemTemplate>
            </asp:TemplateField>
            <asp:BoundField AccessibleHeaderText = "Name" DataField="Name" />
        </Columns>
    </asp:GridView>

Have a script which will be called every time when the ckeck box is checked or unchecked.

<script language="javascript" type="text/javascript">
function GetCheckStatus() {
 var srcControlId = event.srcElement.id;
 var targetControlId = event.srcElement.id.replace('chkIs', 'txtId');
 if (document.getElementById(srcControlId).checked)
      document.getElementById(targetControlId).disabled = false;
 else
      document.getElementById(targetControlId).disabled = true;
}
        </script>

In your aspx.cs page bind the grid with appropriate data source as below.
protected void Page_Load(object sender, EventArgs e)
{
DataTable dt = new DataTable();
dt.Columns.Add("Name");
DataRow dr = dt.NewRow();
dr["Name"] = "Das";
dt.Rows.Add(dr);
DataRow dr1 = dt.NewRow();
dr1["Name"] = "Shon";
dt.Rows.Add(dr1);
gvM.DataSource = dt;
gvM.DataBind();
}

Check this article. I have explained how to make fields editable and noneditable inside gridview using checkbox.

http://www.c-sharpcorner.com/UploadFile/1a81c5/non-editable-fields-in-Asp-Net-gridview/[^]