我如何从后面的代码访问按钮

Question

How can I get access to the button from code behind using id "btnAutocomplete"?

    <asp:GridView DataKeyNames="AutocompleteSchoolChild_Child" Width="1500px" CssClass="table table-bordered" OnDataBound="GridAutocomplete_OnDataBound" 
    ID="GridAutocomplete" runat="server" AutoGenerateColumns="false" AllowPaging="true" DataSourceID="sqlAutocomplete" Visible="true" PageSize="10" 
    OnSelectedIndexChanged="GridAutocomplete_OnSelectedIndexChanged">
     <Columns>
       <asp:TemplateField ItemStyle-HorizontalAlign="Center" ItemStyle-width="80px">
           <ItemTemplate runat="server">
               <asp:Button CssClass="btn btn-default" runat="server" ID="btnAutocomplete" Text="Зачислить" CommandName="Select"/>
           </ItemTemplate>
       </asp:TemplateField>
        ...

Answer 1

Why don't you simply use GetElementById javascript method

document.getElementById("btnAutocomplete").innherHTML("");

Or jQuery:

("#btnAutocomplete").val = "";

As you've asked how to use this, I suggest that you add the code below after your HTML or your aspx layout code which you wrote in your question.

<script type="text/javascript">

    //this function runs when the webpage is loaded
    $(document).ready(function ()
    {
        document.getElementById("btnAutocomplete").innherHTML("whatever you want here");
        //OR
        ("#btnAutocomplete").attr("style","whatever style html you want here");
    });

    //OR declare a private function which you can call through a click event
    function buttonchange()
    {
        ("#btnAutocomplete").val = "whatever value you want to give it";
    }

</script>

You can assign the call event of the private function to some html element, for example:

<button type="button" class="btn" onclick="buttonchange()">Button changer</button>

Answer 2

i think you can define OnRowCommand for your gridview and define command name for your button,see this:

  <asp:GridView DataKeyNames="AutocompleteSchoolChild_Child" Width="1500px" CssClass="table table-bordered" OnDataBound="GridAutocomplete_OnDataBound" 
ID="GridAutocomplete" runat="server" AutoGenerateColumns="false" AllowPaging="true" DataSourceID="sqlAutocomplete" Visible="true" PageSize="10" 
OnSelectedIndexChanged="GridAutocomplete_OnSelectedIndexChanged"
 OnRowCommand="GridAutocomplete_RowCommand">
 <Columns>
   <asp:TemplateField ItemStyle-HorizontalAlign="Center" ItemStyle-width="80px">
       <ItemTemplate runat="server">
           <asp:Button CssClass="btn btn-default" runat="server" ID="btnAutocomplete" Text="Зачислить" CommandName="Select"/>
       </ItemTemplate>
   </asp:TemplateField>

and in code behind:

protected void grdSms_RowCommand(object sender, GridViewCommandEventArgs e)
{
    if (e.CommandName.ToLower() == "select")
   {
     //do something
   }

}

Answer 3

I assume that you want to change button text in currently selected row, so that you need to use FindControl with GridViewRow instance & cast it to a Button control:

protected void GridAutocomplete_OnSelectedIndexChanged(object sender, EventArgs e)
{
    GridViewRow row = GridAutocomplete.SelectedRow;
    Button btnAutocomplete = (Button)row.FindControl("btnAutocomplete");

    btnAutocomplete.Text = "Insert"; // example to use button property
}

If you want to change button text in all GridView rows, you can use foreach loop together with GridViewRow instances on the same event handler:

foreach (GridViewRow row in GridAutocomplete.Rows)
{
    if (row.RowType == DataControlRowType.DataRow)
    {
        Button btnAutocomplete = (Button)row.FindControl("btnAutocomplete");
        btnAutocomplete.Text = "Insert"; // example to use button text property
    }
}

If you're not sure that FindControl cast works properly, change all direct casts to as operator & use null checking like this:

GridViewRow row = (sender as GridView).NamingContainer as GridViewRow;
Button btnAutocomplete = row.FindControl("btnAutocomplete") as Button;
if (btnAutocomplete != null)
{
    btnAutocomplete.Text = "Insert"; // example to use button text property
}

NB: The goal here is getting GridViewRow instance first before accessing button control inside TemplateField , so that SelectedRow is a proper way to get currently selected row.