How to accept null value in GridView from C#

Question

I have a table in my database which passes:

RewardAmountID
Start_Date
End_Date
Reward_Amount

back to my code behind. End_Date can be null but for some reason when i am running my code i am getting an error.

Cannot set Column 'END_DATE' to be null. Please use DBNull instead.

Here is my C# Code.

Amounts = ser.GetRewardAmounts().ToList();

    dt.Columns.Add(new DataColumn("REWARD_AMOUNT_ID", typeof(int)));
    dt.Columns.Add(new DataColumn("START_DATE", typeof(DateTime)));
    dt.Columns.Add(new DataColumn("END_DATE", typeof(DateTime)));
    dt.Columns.Add(new DataColumn("REWARD_AMOUNT", typeof(decimal)));

    foreach (var item in Amounts)
    {
        dr = dt.NewRow();

        dr[0] = item.REWARD_AMOUNT_ID;
        dr[1] = item.START_DATE;
        dr[2] = item.END_DATE;
        dr[3] = item.REWARD_AMOUNT;

        dt.Rows.Add(dr);
    }

    DataView dv = new DataView(dt);

    dg_amounts.DataSource = dv;
    dg_amounts.DataBind();

If anyone has any information on this issue, your help would be great!

@IsThatSo You are correct I have only just realised that thanks alot! — Ben Clarke
– Ben Clarke, Commented Nov 6, 2014 at 12:10
Actually this has nothing to do with asp.net and grid view, but with ADO.NET. I have fixed the tags accordingly. — Patko
– Patko, Commented Nov 6, 2014 at 12:23

Patko · Accepted Answer · 2014-11-06 12:07:13Z

2

Actually all the information you need is already in the exception message - you are obviously trying to set a null value to a DataColumn. The problem is that DataColumn doesn't use nulls, but DBNull. So you could do it like this:

dr[2] = DCRA.END_DATE ?? DBNull.Value;

answered Nov 6, 2014 at 12:07

Patko

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3 Comments

Ben Clarke Over a year ago

Thanks for helping! I knew i had to allow it null somewhere. I tried adding AllowNulls to my GridView and it didnt work. Thanks for the answer.

Ben Clarke Over a year ago

Is there a way to say if its Null dont display anything in the datagrid for that cell?

Patko Over a year ago

Check this answer stackoverflow.com/questions/15218714/… for displaying null in DataGrid.

Maunet · Accepted Answer · 2014-11-06 13:05:37Z

0

Please use this property to handle null values into grid.

Property : nulldisplaytext="xxx"

answered Nov 6, 2014 at 13:05

Maunet

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