displaying data from gridview ASP4.0 - C#

faraz akram

16y9.9k.NET

hi
i have a panel having grid view with only tow columns one is CHECKBOX and other is id, need to show data on right side of the grid of the specific row on selecting the check box C#
i have populated the datagrid and added a templeta control as check box i have also fired this event on checkbox changed
GridView1_SelectedIndexChanged1
one it comes to get the value of specifis cell throwing me exception "object refrence not set at the instance of..... use the new key word"
any fruitfull suggestions
thanks in advance

6 Replies

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karthick kumar16y ago
hi,
First of all check whether the row is selected or not .you mentioned that u have only two columns one is CHECKBOX and other is id. when u try to get the Cells[3] value u may get this exception.provide exact cell value.

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Manikavelu Velayutham16y ago
You need to loop through the rows in gridivew.
Find the check box control in each row and check for the checked value, if its true, then find the nth columns value...
CheckBox chkName = (CheckBox )GridView1.Rows[count].FindControl("chkName");
if (chkName.Checked == true)
{
// do your code here
}

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faraz akram16y ago
u r right , and i have done all of the above, problem is that check box event is not actually selecting the row that is y the row and cell both ar null throwing this exception
My question is that how i would b able to select a datagrid row through an item template check box in order to get the columns values.
thanks in adv
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Manikavelu Velayutham16y ago
There is two possiblities of error.
1. There is no selectedrow in the grid, so you just need to check selectedrow not equals to null there
2. There is no Cells[3] in that selectedrow. before using the cells[3], you need to check not equals to null.

To solve this issue, put a debugger in that line and add a quick watch to see the exact output.
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faraz akram16y ago
this is for adding a check box in datagrid :
<asp:TemplateField HeaderText="Select">
<ItemTemplate>
<asp:CheckBox ID="chkSelect" runat="server" AutoPostBack="True"
oncheckedchanged="chkSelect_CheckedChanged" />
ItemTemplate>
<HeaderTemplate>
HeaderTemplate>
asp:TemplateField>

and this is code behind for check box check changed
GridViewRow row = GridView1.SelectedRow;
string s = GridView1.SelectedRow.Cells[3].Text; ----> here comes the exception
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Manikavelu Velayutham16y ago
It seems to be checkbox was not found through your code. Hence the error object reference not found.
can you paste your code here, so that we can easily fix the bug in your code

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