I have the following code where I am attempting to count the rows under each grouping/band in a DataTable. This is currently counting ALL rows in the specified band index and returning that value to all band1 rows. I need a way of counting rows under each band in band1 and not all rows under band1, then return that value to each summary band. This is not the end result desired but I think I can finish if I can just get each band to have a unique value for rows under it rather than all rows applying the same specified condition.
foreach (DataRow rows in dataSetDS.Tables["dataTable1_band1"].Select())
{
rows["column"] = dataSetDS.Tables["dataTable1_band2"].Rows.Count.ToString();
}
Current output to Excel using syntax above.
Desired output:
I am using a datagridview to show data in csv file. One of the column in datagridview in of numeric type [Column name: ID].
I am using autosort method of datagridview(sorting by clicking column header).
This works well for all the columns except this numeric column.
This column contains numbers 1 to 55
What I am getting now is after sorting is:
1,10,11,12,13,14,15,16,17,18,19,2,20,21,22,23,24,25,26,27,28,29,3,30,31...
...and so on. what I want is:
1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,...
Please help.
Thanks in advance.
You can use the event SortCompare like this:
private void dataGridView1_SortCompare(object sender, DataGridViewSortCompareEventArgs e) {
//Suppose your interested column has index 1
if (e.Column.Index == 1){
e.SortResult = int.Parse(e.CellValue1.ToString()).CompareTo(int.Parse(e.CellValue2.ToString()));
e.Handled = true;//pass by the default sorting
}
}
Build your DataTable:
DataTable dt = new DataTable();
dt.Columns.Add("ID", typeof(Int32));
dt.Columns.Add("Name");
dt.Columns.Add("ForeName");
I am using these columns due to the fact that I don't know what data you are storing.
After reading your csv-file you have to iterate through the data. Considering you have your data stored in a String array (String[][] arr) with the inner ArrayLength of 3 (ID, Name, ForeName).
for(int i=0;i<arr.Length;i++)
{
DataRow row = dt.NewRow();
row["ID"] = Convert.ToInt32(arr[i][0]);
row["Name"] = arr[i][1];
row["ForeName"] = arr[i][2];
dt.Rows.Add(row);
}
DataGridView dgv = new DataGridView();
dgv.DataSource = dt;
I hope this helps, it's a sample Code.
The reference to DataTable: https://msdn.microsoft.com/de-de/library/system.data.datatable(v=vs.110).aspx
EDIT
I just read that you already have a DataTable as result. You can build another DataTable as I did and iterate through your Data and convert the ID to an Integer. Please don't forget to set the Columns Type:
dt.Columns.Add("ID", typeof(Int32));
Well, your column is not numeric, but a text column that contains numeric string values. There's a huge difference! A real numeric column would apply numeric sorting, while your column uses alphanumeric sorting.
I'd try to actually change the underlying data type to int instead of string or apply manual sorting as suggested by lem2802.
Please add some information about how you fill the data grid view. Maybe that can help find an easier way than implementing a manual sort comparison.
According to your comment you create a DataTable as the data source for the grid view. You need to make sure that the column(s) containing numeric values also have a numeric type. In the code where you create the table and its columns, do something like this:
DataTable table = new DataTable();
table.Columns.Add("ID", typeof(Int32));
... // Other columns
Later when you create the rows based on the content of your CSV file, make sure to fill each row so that the value for the ID column actually is an int:
DataRow row = table.NewRow();
row["ID"] = Convert.ToInt32(idValueFromCSV);
... // Other columns
That way you'll get what you want without implementing custom sorting.
I have a Datatable, and I need to add "id" or "index" column with auto value.
like a identity column in sql.
I have a function that return me the start index: GetID();
I need that the value of this column in the first row will be the value that GetID() return, the value in the second row will be GetID() + 1.... GetID() + 2 ...
I need to do this without loops .
I thought to use "Expression" when I create new column, but I dont know how to do this.
You can use AutoIncrement property of DataTable column:
var dt = new DataTable();
var col = dt.Columns.Add("ID", typeof (long));
col.AutoIncrement = true;
col.AutoIncrementSeed = GetID();
col.AutoIncrementStep = 1;
But it will work only for rows being added to your DataTable after adding this column.
If you adding this identity column to the DataTable with existed rows - this will not update existed rows, so in this case you're still need loop over your existed rows and update them manually.
Its kind of subjective question to ask but still i hope i will find help.
I was learning about merging two tables from database to a singe DataTable.Then i came accross the following block of code.
DataTable mdt = new DataTable();
mdt.Columns.Add("products");
mdt.Columns.Add("price");
for (int i = 0; i < A.Rows.Count; i++)
{
DataRow dr = mdt.NewRow();
dr["product"] = A.Rows[i]["product"].ToString();
dr["price"] = A.Rows[i]["price"].ToString();
//A is a DataTable
mdt.Rows.Add(dr);
}
I can understand that the datas are being added to the row of a Datatable.
This is what i understood:
The column product of DataTable is assigned a value by dr["product"].Correct me if i am wrong.But how is this A.Rows[i]["product"].ToString(); working.
This should help:
A = DataTable
A.Rows = Collection of DataRows in A
A.Rows[i] = i-th row from collection
A.Rows[i]["product"] = Column "product" in row (return type of expression is object)
So when you do dr["product"] = A.Rows[i]["product"].ToString();, you are assigning the value of the product column of the current row from datatable A to the product column in your new data row. Similarly for the price column.
Rows[i] represents the index to which the value is assigned.I mean for the first loop the value is 0,for second loop the value is 1.So for the firs loop the values of product and price are added to first row with index 0.Similarly for the second loop the values of product and price are added to the second row with index 1.
And for the second part ie ["product"].ToString(),its simply converting the value of product to string.
EDIT
Since A is a Datatable which is already filled.What we are doing with that statement is,we are taking the DataTables's i-th row from the collection,converting it to string and assigning it to the column "product" in the datarow.
The ["product"].ToString() Is taking the value of the cell with the column name product, and converting it to a string to be assigned to your new row.
I have a labels that need values retreieved from a Database.
I am able to query the database but how can I extract values from a DataTable and place them in the appropiate labels
Thanks
In DataTable you have rows and columns. To select a particular cell you need to do this:
label1.Text = dataTable[0][0];
This will set the label1 text to Row 0, Column 0 value.
To iterate through each row use:
foreach(DataRow row in dataTable.Rows)
{
Console.WriteLine(row["ColumnName1"]);
Console.WriteLine(row["ColumnName2"]);
Console.WriteLine(row["ColumnName3"]);
Console.WriteLine(row["ColumnName4"]);
}
This will print values for columns against each row. In this code you need to replace string for columnname (e.g. ColumnName1) with your column names
Example of how you retrieve a value from the first row and the column named "MyFirstColumn":
label1.Text = myDataTable.Rows[0]["MyFirstColumn"]