每当列值等于特定值时，如何隐藏 datagridview 行

Question

So for example,

I have this datagridview which is bounded to a datatable:

A	B	C
1	4	7
2	5	8
3	6	9

And B is the column I want to check the value for, for example I have a saved int value of 5. The code should check if in B column there is a value of 5, if true the all the rows with value 5 visibility is set to true, and all other rows will have their visibility set to false.

Fow now, I have tried this little code (though it checks the all cells but not by specific column):

            foreach (DataGridViewRow row in dataGridView1.Rows)
            {
                for (int i = 0; i < row.Cells.Count; i++)
                {
                    int rowIndex = row.Index;
                    if (row.Cells[i].Value.ToString().Equals("16"))
                    {
                        CurrencyManager currencyManager1 = (CurrencyManager)BindingContext[dataGridView1.DataSource];
                        currencyManager1.SuspendBinding();
                        dataGridView1.Rows[rowIndex].Visible = true;
                        currencyManager1.ResumeBinding();
                    }
                    else
                    {
                        CurrencyManager currencyManager1 = (CurrencyManager)BindingContext[dataGridView1.DataSource];
                        currencyManager1.SuspendBinding();
                        dataGridView1.Rows[rowIndex].Visible = false;
                        currencyManager1.ResumeBinding();
                    }
                        
                }
            }

Now about this CurrencyManager, when I tried to hide the rows without it, it simply error'd me, but now with it all rows visibility set to false. And the problem is I don't understand where to look at and how to fix it, even if the code checks the cells the value "16" in code should show some rows in datagridview but it doesn't.

Answer 1

It's a lot simpler. For a datagridview bound like this:

myDgv.DataSource = dt;

We can dynamically filter the dgv like this:

dt.DefaultView.RowFilter = "[B] = 5"; //only show rows where B is 5

When a DGV's DataSource is set to a datatable it binds to the DataView exported by the DefaultView property so that you can change properties of the view like filter and sort, and it will influence the DGV. You also have the option of creating your own DataView based on the table and binding the DGV to that. For more info on the syntax you can use in a RowFilter, look at DataColumn.Expression

When working with bound data, do try to get into the habit of accessing the data by looking in the container (the datatable) rather than enumerating the DGV and pulling values out of it

You might find it more useful to bind your datatable to a BindingSource and then bind the BindingSource to the DGV- a bindingsource also has a Filter property with the same syntax but also maintains the notion of current row/ as the user changes the current row in the DGV the value of the Current property on the bindingsource changes, making it easier to manipulate the current row in code

---

You indicate that this is all set up in the forms Designer, which means on your form you have:

• a datagridview called _xDataGridView
• a binding source called _xBindingSource
• a dataset called _xDataSet
• the bindingsource's DataSource is set to the dataset and the datamember is set to the table name in the dataset, and the datagridview's DataSource is set to the bindingsource

(mostly I'm just describing the setup to make sure it's right)

All you need to do is:

_xBindingSource.Filter = "[B] = 5";