Index was out of range. Must be nonnegative and less than the size of the collection

Question

1.00/5 (1 vote)

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C#

<blockquote class="quote"><div class="op">Quote:</div><blockquote class="quote"><div class="op">Quote:</div> try
            {
                if (cn.State.ToString() != "Open")
                    cn.Open();


                for (int i = 0; i < 10; i++)
                {
                    cmd = new SqlCommand("select fahsName from Name_fahs where Number_N='1'  and Number_of_each_Name='"+i+1+"'", cn);
                    dr = cmd.ExecuteReader();
                    dr.Read();
                    dataGridView1.Rows[i].Cells[i].Value = dr["fahsName"].ToString();
                    
                    dr.Close();
                }
               
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message + "jwnjew ");
            }
            finally 
            {<pre lang="c#">

cmd.Cancel();
cn.Close();
}

What I have tried:

C#

<blockquote class="quote"><div class="op">Quote:</div><blockquote class="quote"><div class="op">Quote:</div> try
            {
                if (cn.State.ToString() != "Open")
                    cn.Open();


                for (int i = 0; i < 10; i++)
                {
                    cmd = new SqlCommand("select fahsName from Name_fahs where Number_N='1'  and Number_of_each_Name='"+i+1+"'", cn);
                    dr = cmd.ExecuteReader();
                    dr.Read();
                    dataGridView1.Rows[i].Cells[i].Value = dr["fahsName"].ToString();
                    
                    dr.Close();
                }
               
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message + "jwnjew ");
            }
            finally 
            {<pre lang="c#">

cmd.Cancel();
cn.Close();
}

Posted 26-Nov-18 5:05am

waleed_akre

Updated 26-Nov-18 5:27am

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2 solutions

Solution 1

dataGridView1.Rows[i].Cells[i].Value = dr["fahsName"].ToString();

Check that "i" is valid here. If i is 3 and there are not at least 4 rows then you'll get this error, or if the fourth row doesn't have at least 4 cells you'll get the error. Basically this code will only work if you've already populated your datagridview with enough rows and columns. If you're looking to build the grid as you go then things don't come into existence as you reference them, you'll need to explicitly create them. So google how to add rows and cells to a datagridview.

Posted 26-Nov-18 5:24am

F-ES Sitecore

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OriginalGriff · Accepted Answer · 2018-11-26T05:27:00

Look at the error message:

C#

Index was out of range. Must be nonnegative and less than the size of the collection

It couldn;t be a lot clearer if it tried!

You are accessing an array via an index and it is either negative or too big for the array. For example,

C#

int[] m = new int[3];

Can only be access ed as

C#

int i1 = m[0];
int i2 = m[1];
int i3 = m[2];

Any other value will give you this error.

In your code, you are trying to access the DGV at locations

[0,0]
[1,1]
[2,2]
[3,3]
[4,4]
[5,5]
[6,6]
[7,7]
[8,8]
[9,9]

So unless your DGV has at least 10 rows and at least 10 columns, it will fail.
I suspect that you meant to reference a specific column for all the rows, rather than a diagonal.

Why not do a single SqlCommand and with

SQL

... WHERE Number_Name = '1' AND Number_of_each_Name BETWEEN 0 AND 9

instead of doing multiple round trips to the server?