CODEWITHSUNDEEP
c#classdatagridviewdatatable
Hexxed
Hexxed

Reputation: 683

Converting unbound DataGridView to a DataTable

I'm trying to convert my datagridview dgvInput from Form1 to a DataTable in an another class Queries in preparation for SqlBulkCopy. I pass dgvInput to a method SaveAll in my class Queries with a parameter DataGridView dgv.

Form1:

public void convert2DT(DataGridView dgv)
{
    Queries qry = new Queries();
    qry.SaveAll(dgvInput);
}

Class:

class Queries {

public void SaveAll(DataGridView dgv)
    {
        foreach (DataGridViewRow dr in dgv.Rows)
        {
            //Create table and insert into cell value.
            DataRow dataRow = dt.NewRow();
            for (int i = 0; i < noOfColumns; i++)
            {
                if (i == 0)
            >>  { dataRow[i] = DateTime.Parse(dr.Cells[i].Value.ToString()); }
                else if (i == 7)
                { dataRow[i] = int.Parse(dr.Cells[i].Value.ToString()); }
                else
                { dataRow[i] = dr.Cells[i].Value.ToString(); }
            }
            dt.Rows.Add(dataRow);
        }
    //SqlBulkCopy Codes
    }
}

I'm getting NullReferenceException on line >>.
Error Message: Object reference not set to an instance of an object. I have tried setting New to the dgv. However, I still get an Exception. From what I've researched the Nested for loops SHOULD do the job right.

How can I resolve this?

Upvotes: 1

Views: 376

Answers (1)

Ian
Ian

Reputation: 30813

The problem is because your dr.Cells[i].Value is null and that is caused by the empty last row due to the option AllowUserToAddRows = true as you figure out later. To solve it, you might put AllowUserToAddRows = false as what you have done.

But better still to check if dr.Cells[i].Value is not null before processing it to make it more robust towards null cell value wherever it may be found:

for (int i = 0; i < noOfColumns; i++)
{
    if (dr.Cells[i].Value == null)
        continue; //don't process
    if (i == 0)
    { dataRow[i] = DateTime.Parse(dr.Cells[i].Value.ToString()); }
    else if (i == 7)
    { dataRow[i] = int.Parse(dr.Cells[i].Value.ToString()); }
    else
    { dataRow[i] = dr.Cells[i].Value.ToString(); }
}

And use continue to ignore the null cell. Use AllowUserToAddRows = false only if you really mean it; that is, to prevent user to add rows, not to protect against cell's null value.

Upvotes: 1

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