Get value of gridview.selected.row[] with visible property = 'false' - asp.net

Question

Hi from this field in my gridview, I'd like to pass the id value when the select command field is clicked, but i don't want to have the id field visible so I have the visible property set to false; however, when I pass it on the SelectedIndexChanged event the value is "" yet when the visible property is set to "true" the text value passes fine. What is the correct way to do this?
<asp:BoundField DataField="Project_ID" Visible="false"/>
protected void GridView1_SelectedIndexChanged(object sender, EventArgs e)
{
String ProjID = GridView1.SelectedRow.Cells[10].Text;
}

Answer 1

Try this:
.aspx
<asp:Gridview id="GridView1" runat="server" DataKeyNames="Project_ID" />
.cs
protected void GridView1_SelectedIndexChanged(object sender, EventArgs e)
{
if(gridView.SelectedDataKey != null)
{
var selectedId = GridView1.SelectedDataKey.Value;
}
}
Here you'll find more info about DataKeys in Gridviews: http://msdn.microsoft.com/de-de/library/system.web.ui.webcontrols.gridview.selecteddatakey(v=vs.110).aspx

Answer 2

I have done something like this in winform maybe can help you. That is what i used
int rowindex = dataGridView1.CurrentRow.Index;
string ProjID= dataGridView1.Rows[rowindex].Cells[10].Value.ToString();

Answer 3

you could use HiddenField inside your gridView ItemTemplate to keep the ID and use it in onrowcommand event, like below:
.aspx
<asp:GridView ID="gridProject" runat="server"
onrowcommand="gridProject_RowCommand">
<Columns>
<ItemTemplate>
<asp:HiddenField ID="hidProjectID" runat="server"
Value='<%# ((DataRowView)Container.DataItem)["Project_ID"] %>' />
<asp:Button ID="btnProject" runat="server" Text="use pro id"
CommandArgument="<%# ((GridViewRow) Container).RowIndex %>"
CommandName="DoSomething"></asp:Button>
</ItemTemplate>
</Columns>
</asp:GridView>
aspx.cs
protected void gridProject_RowCommand(object sender, GridViewCommandEventArgs e)
{
int index = 0;
GridViewRow gridRow;
GridView grid = sender as GridView;
try
{
switch (e.CommandName)
{
case "DoSomething":
index = Convert.ToInt32(e.CommandArgument);
row= gridProject.Rows[index];
string Id = ((HiddenField)row.FindControl("hidProjectID")).Value;
//do whatever you want here
break;
// and you can have as many commands as you want here
}
}
catch { //display error }
}