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Get dynamically created checkbox value from Gridview | Asp.net

I have this gridview where I need to populate more than 25 database tables. These table are lookup table and this gridview is for lookup table maintenance purpose.
Instead of putting specific columns in gridview I directly bind the dataTable to gridview.
This below method assigns the (last column in gridview) active column's value which is "y"/"n" to checkbox.
<asp:GridView ID="gvTables" runat="server" CssClass="Grid" Width="100%" AutoGenerateColumns="true" Font-Names="Arial"
BorderWidth="1" PagerSettings-Mode="Numeric" Font-Size="8.7pt" Font-Bold="false" AlternatingRowStyle-BackColor="#f4f4f4"
HeaderStyle-BackColor="LightGray" AllowPaging="True" ShowFooter="false" PageSize="12"
OnPageIndexChanging="gvTables_PageIndexChanging"
OnRowDataBound="gvTables_RowDataBound"
OnRowCreated="gvTables_RowCreated"
OnSelectedIndexChanged="gvTables_SelectedIndexChanged">
<PagerStyle CssClass="pgr" />
</asp:GridView>
code:
private void SetCheckBoxesInGV()
{
////add checkboxes in place of active
for (int i = 0; i < gvTables.Rows.Count; i++)
{
System.Web.UI.WebControls.CheckBox chk = new System.Web.UI.WebControls.CheckBox();
chk.ID = "chk";
chk.Checked = gvTables.Rows[i].Cells[gvTables.Rows[0].Cells.Count - 1].Text.Trim() == "y" ? true : false;
gvTables.Rows[i].Cells[gvTables.Rows[0].Cells.Count - 1].Controls.Add(chk);
gvTables.Rows[i].Cells[gvTables.Rows[0].Cells.Count - 1].ControlStyle.CssClass = "ItemCenter";
}
}
So the last column looks like this instead of y/n.
Now I want to get the checkbox values, I am using this and thought it will work but it doesn't. Gives null value and "Object reference not set to an instance of an object".
((CheckBox)gvTables.Rows[i].Cells[gvTables.Rows[0].Cells.Count - 1].FindControl("chk")).Checked

So what I did was I added a template field for checkbox and used this link's help to re arrange the columns so that the checkBox column be the last column.
And then I was able to get the checkbox value easily.

Append GridView-Columns after DataTable was databound

I have a DataTable which I have created in code file and I later bind it to a GridView which i have created by using the drag and drop feature of Visual studio.
However I have added some columns in the GridView which are not supported(correct me if I am wrong) in a DataTable, e.g Hyperlink-Column or CheckBox-Column.
I would like to build the hyperlink column and the checkbox id's with a value derived from a value generated in the DataTable from a particular column. I know I can use DataNavigateUrlfields to build dynamic links but how do I do this with a DataTable that is to be bound later?
I also need the columns in the GridView to appear after the columns in the DataTable.
Any help in the above will be highly appreciated. Any alternatives are also appreciated.

Declaratively added controls will be created first and then the databound/manually created(documented in the Page's Lifecycle, s‌​earch for "controls created declaratively"). Since you want the declarative columns last, you need a hack:
You could use RowDataBound to change the order, so that the AutoGenerated columns are followed by your other columns like Hyperlink or CheckBox columns:
protected void gridOffers_RowDataBound(object sender, GridViewRowEventArgs e)
{
TableCell cell = e.Row.Cells[0];
e.Row.Cells.RemoveAt(0);
//Move first to the end
e.Row.Cells.Add(cell);
cell = e.Row.Cells[0];
e.Row.Cells.RemoveAt(0);
//Move second to the end
e.Row.Cells.Add(cell);
}
However I have added some columns in the GridView which are not
supported(correct me if I am wrong) in a DataTable, e.g
Hyperlink-Column or CheckBox-Column.
They don't need to be supported in the DataTable but in the GridView. The table contains your data and the grid contains the view.

You can try with this code - based on RowDataBound
<Columns>
<asp:TemplateField>
<ItemTemplate>
<asp:HyperLink ID="HyperLink1" runat="server" Text=""></asp:HyperLink>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField>
<ItemTemplate>
<asp:CheckBox ID="CheckBox1" runat="server" />
</ItemTemplate>
</asp:TemplateField>
</Columns>
You can adjust you datbound with your event RowDataBound, i added HyperLink control, in order to customize your link as you want.
void GridView_RowDataBound(Object sender, GridViewRowEventArgs e)
{
if(e.Row.RowType == DataControlRowType.DataRow)
{
var hyperLink = (HyperLink)e.Item.FindControl("HyperLink1");
hyperLink.NavigateUrl ="....";
var checkBox = (CheckBox)e.Item.FindControl("CheckBox1");
checkBox.Checked =....
}
}

Well there is an easy way to append a column if you are using datatable
DataTable yourDataTable = new DataTable();
Load yourDataTable by DataReader or DataAdapter
DataColumn newColumn = yourDataTable.Columns.Add("Total", typeof(Int32));
After that you can bind this datatable into your Gridview.
msdn

changing order of boundfield in gridview

i am trying to develop one application, the data displayed in Gridview. gridview contains many boundfield colums . I recently add a column after the end of last boundfield column of gridview (Imported boundfield column). so i have less chance to move the last boundfield to desired location in mark up. if i move the column to desired place, then i've to modify entire coding while row _databounding. so is there any way we can re order the columns without changing in mark up ?? ..
<asp:BoundField DataField="someData" HeaderText="SomeData"> </asp:BoundField>
<asp:CommandField UpdateText="Update" EditText="Edit" CancelText="|Cancel" ShowEditButton="true" ControlStyle-CssClass="LinkNormal" />
<asp:BoundField DataField="someData2" HeaderText="Imported"> </asp:BoundField>
out put will be like this (EDit/Delete/Imported are boundfield columns )
SomeData | Update| Imported
what i need now gridview shoud display like this
Imported | SomeData | Update

I would suggest moving away from using column indexes, and start using data keys to reference column values in the code-behind. That way, you can change the markup and move columns around without effecting the code-behind.
<asp:GridView ID="GridView1" runat="server" DataKeyNames="Col1, Col2, Col3" ... >
Using data keys, you can get column values like this in the RowDataBound event:
protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
string col1 = GridView1.DataKeys[e.Row.RowIndex]["Col1"].ToString();
}

It seems, that GridView hasn't such functionailty. Instead of, you can try to obtain indexes of columns in code behind by for example column's header text, below is such function that does the job:
int getColumnIndexByHeaderText(GridView gridView, string headerText)
{
for (int i = 0; i < gridView.Columns.Count; ++i)
{
if (gridView.Columns[i].HeaderText == headerText)
return i;
}
return -1;
}
And use it instead of hardcoded column indexes.

ASP.NET Add column to Gridview

I have a gridview that is displaying data from a database using LINQ to SQL.
AssetDataContext db = new AssetDataContext();
equipmentGrid.DataSource = db.equipments.OrderBy(n => n.EQCN);
I need to add a column at the end of the girdview that will have links to edit/delete/view the row. I need the link to be "http://localhost/edit.aspx?ID=" + idOfRowItem.

Try adding a TemplateField to your GridView like so:
<Columns>
<asp:TemplateField>
<ItemTemplate>
Edit
</ItemTemplate>
</asp:TemplateField>
</Columns>
Within the item template you can place any links you like and bind any data you wish to them from your DataSource. In the example above I have just pulled the value from a column named id.
As things stand this would work fine, however the column above would be aligned left most in the GridView with all the auto generated columns to its right.
To fix this you can add a handler for the RowCreated event and move the column to the right of the auto generated columns like so:
gridView1.RowCreated += new GridViewRowEventHandler(gridView1_RowCreated);
...
void gridView1_RowCreated(object sender, GridViewRowEventArgs e)
{
GridViewRow row = e.Row;
TableCell actionsCell = row.Cells[0];
row.Cells.Remove(actionsCell);
row.Cells.Add(actionsCell);
}
Hope this helps.

Dataset datatable formatting rows

Hi i have a dataset which contains a table retrieved from sql. It has 'product' column and 'price' column. I got the dataset and binded to grid. Now i want to make the grid's price column to be formatted to 2 decimal places(validation). Any idea please.
I should not change the select query since its an SP which gives me the dataset.

if you neither want to use Bound-Field nor change select query than as much i know you have two options left to accomplish this. First is, do value change in your dataset before binding to grid using any loop and the second option is alter values in grid on RowDataBound Event...
By altering value in Dataset:
foreach(dataRow[] dr in dataset.tables[your table index])
{
// max. two decimal places
string val = String.Format("{0:0.##}",Convert.ToDecimal(dr[column index]));
dr[column index] = val;
}
By altering value in Grid:
protected void mygrid_OnRowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
mygrid.cell[cell index].Text = String.Format("{0:0.##}",Convert.ToDecimal(dataset.tables[table index][column index][Row Index]));
}
}
Now if you want apply validation for data insert and update you can apply RegularExpressionValidator at your textBox ...
<EditItemTemplate>
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
<asp:RegularExpressionValidator ID="RegularExpressionValidator1" runat="server" ErrorMessage="RegularExpressionValidator"
ControlToValidate="TextBox1" ValidationExpression="^\d{1,2}([.]\d{1})$"> ValidationGroup="MyVal"</asp:RegularExpressionValidator>
Now you have to apply
ValidationGroup="MyVal"
also on click control on which you'll perform its editing and update..

Try this:
<asp:BoundField DataField="Price" DataFormatString="{0:C2}" HeaderText="Price" />
You need to add the "DataFormatString" property to the bound field as shown above. This formats currency values to two decimal places. Check this article.
DataField refers to the name of the column in the datatable, whereas the HeaderText refers to the text which would be shown as the header of the column in grid.