problem with empty field in gridview when updating

Valerie Meunier

When editing a row of a gridview, some fields can remain empty.

But with this code, i get the error (if field 'name" remained empty) when updating: "Object reference not set to an instance of an object.":

protected void GridView1_RowUpdating(object sender, System.Web.UI.WebControls.GridViewUpdateEventArgs e)

string name;

name = e.NewValues["name"].ToString();

I tried to prevent that with this code:

if (string.IsNullOrEmpty(e.NewValues["name"].ToString()) == true)

name = e.NewValues["name"].ToString();

else

name ="";

But I get the same error (at line if ...)

Thanks for help.

5 Replies

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Salman Beg5y ago
Accepted answer
Remove == true from your if condition. Also don't use ToString() and in place of that you can use Convert.ToString(e.NewValues["name"]) Thanks
Valerie Meunier5y ago
Hi guys, i finally found the solution:
this works:
string name;
if (Convert.ToString(e.NewValues["name"]) != "")
vnaam = e.NewValues["name"].ToString();
else
name = "";

This gives the error: Object reference not set to an instance of an object.:
string name;
name = e.NewValues["name"].ToString() == null ? "" : e.NewValues["name"].ToString();
or

name = e.NewValues["name"].ToString() == ""l ? "" : e.NewValues["name"].ToString();
Valerie Meunier5y ago
Ok, i was too fast. Sorry.

if (Convert.ToString(e.NewValues["vnaam"])) gives "cannot convert string to bool"

With (Convert.ToBoolean(e.NewValues["vnaam"])), i get an error when the field is filled:"

String was not recognized as a valid Boolean.

With name = e.NewValues["name"].ToString()==null?"":e.NewValues["name"].ToString();

i get the error: CS0165: Use of unassigned local variable name at the line (a little bit further):
if (name == "")
{e.Cancel = true;
Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "myscript", "
alert('name is empty.');", true);
nametxt.Focus(); }
Thanks.
Valerie Meunier5y ago
Hi, thanks both for replying.

I tried the solution of Salman Beg but it works like this:
if (Convert.ToBoolean(e.NewValues["name"]))

Tomorrow, i'll try the solution of Sachin Singh.
Sachin Singh5y ago
test this
name = e.NewValues["name"].ToString()==null?"":e.NewValues["name"].ToString();