简体   繁体   中英

Rows cannot be programmatically added to the datagridview's row collection when the control is data-bound

First of all, I looked up this related question in here but the solution dataGridView1.Rows.Add() doesn't work in my case.

In my Datagridview, I have 3 TextBoxes for data input and 2 ComboBoxes for the user to choose the values (which are bound into the database). One of my TextBoxes is set to read only so that the users can only populate it outside the datagrid (with a normal TexBox and a Button).

When the users fill a DataGridView with data, there is always an empty row at the bottom; so I disable this and I used this code to prevent the users from adding a new row inside the datagrid...

dataGridView1.AllowUserToAddRows = false

I only want to add a new row when the users click the button I mentioned above (which throws an error).

The error message I got was:

"Rows cannot be programmatically added to the datagridview's row collection when the control is data-bound"

示例图像 the one with a red arrow is a ComboBox, and the one with green arrow is a read only TextBox

It appears as though you are using the DataSource property of the DataGridView. When this property is used to bind to data you cannot explicitly add rows directly to the DataGridView. You must instead add rows directy to your data source.

For example if your data source is a DataTable, using the DataTable that is assigned to the DataSource property (untested):

private void AddARow(DataTable table)
{
    // Use the NewRow method to create a DataRow with 
    // the table's schema.
    DataRow newRow = table.NewRow();

    // Add the row to the rows collection.
    table.Rows.Add(newRow);
}

You can get the DataGridView 's DataSource and cast it as a DataTable .

Then add a new DataRow and set the fields' values.

Add the new row to the DataTable and Accept the changes.

In C# it would be something like this:

DataTable dataTable = (DataTable)dataGridView.DataSource;
DataRow drToAdd = dataTable.NewRow();

drToAdd["Field1"] = "Value1";
drToAdd["Field2"] = "Value2";

dataTable.Rows.Add(drToAdd);
dataTable.AcceptChanges();

After adding a new row, you have to set the row index in boundary of row count. You have to do these steps.

  1. First, add row in DataGridView:

     dataGridView1.Rows.Add();
  2. Second, set new row index to count - 1:

     int RowIndex = dataGridView1.RowCount - 1;
  3. Then at last, set the controls values in it:

     DataGridViewRow R = dataGridView1.Rows[RowIndex]; R.Cells["YourName"].Value = tbName.Text;

And if your datagrid's source is datattable you have to add row in that table.Give new values to the newly added row in data table and at last rebind the datagrid with updated datatable.

    DataRow row = dt.NewRow();  
    row["columnname"] = tbName.Text.toString();  
    dt.Rows.Add(row);
    dt.AcceptChanges();  

   dataGridView1.DataSource = dt;  
   dataGridView1.DataBind();

Check if you have set the index of the new row properly. Perhaps that's why you are getting this error.

The Bound Datagridview has a problem that when you want to add your data programmatically it prevent it to add it directly. so the indirect and best way to add data is like this.. and remember never add data directly to datagridview programmatically because it create problem always, add data to your datasource instead :-)

code for VB.NET
Dim r As DataRow ( C# : Datarow r=new Datarow() below codes apply to C# also)
r = dataset.Tables(0).NewRow
r.Item("field1") = "2"
r.Item("field2") = "somevalue"
dataset.Tables(0).Rows.Add(r)

dataset.Tables(0).acceptchanges()

the update will goes as you do ever

The best solution I found:

//create datatable and columns
DataTable dtable = new DataTable();
dtable.Columns.Add(new DataColumn("Column 1"));
dtable.Columns.Add(new DataColumn("Column 2"));

//simple way create object for rowvalues here i have given only 2 add as per your requirement
object[] RowValues = { "", "" };

//assign values into row object
RowValues[0] = "your value 1";
RowValues[1] = "your value 2";

//create new data row
DataRow dRow;
dRow = dtable.Rows.Add(RowValues);
dtable.AcceptChanges();

//now bind datatable to gridview... 
gridview.datasource=dtable;
gridview.databind();

Source: http://www.codeproject.com/Questions/615379/Adding-rows-to-datagridview-with-existing-columns

When I write this line in Form_Load

DGVData.DataSource = DataSQLite.GetData("SELECT * from tableName");

And trying to add a new row this error appeared to me

Instead of using DataSource try this code

 private void Form_Load(object sender, EventArgs e) {
        DataSQLite.OpenDB();      // this line to open connection to Database and DataSQLite class i created it
        DataTable tbl = DataSQLite.GetData("SELECT * from tableName");
        for (int i = 0; i < tbl.Rows.Count; i++) {
            DGVData.Rows.Add();  // this line will create new blank row
            for (int j = 0; j < Numberofcolumns; j++) {
                DGVData.Rows[i].Cells[j].Value = tbl.Rows[i][j].ToString();
            }
        }
    }

After this code you can easily add rows

The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.

 
粤ICP备18138465号  © 2020-2024 STACKOOM.COM