c# datagridview vertical scroll too slow in WrapMode + AutoSizeRowsMode

Question

I am displaying multi-line text in DataGridView Cell.
To show multiline text I need to set WrapMode = true and AutoSizeRowsMode = allcells.
If AutoSizeRowsMode = none, I can't use it because the entire contents are not displayed and only a portion is displayed.

However, setting wrapmode = true and AutoSizeRowsMode =allcells is too slow to scroll vertically using the mouse wheel.
I want to scroll vertically quickly and naturally.

May I ask for some advice?

using System;
using System.Data;
using System.Windows.Forms;

namespace test_dataGridView
{
    public partial class Form1 : Form
    {
        private DataTable tb;
        [System.Runtime.InteropServices.DllImport("user32.dll")]
        public static extern int SendMessage(IntPtr hWnd, Int32 wMsg, bool wParam, Int32 lParam);
        private const int WM_SETREDRAW = 0x000B;
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            tb = new DataTable("itemTable");
            DataColumn[] cols ={
                                  new DataColumn("No",typeof(String)),
                                  new DataColumn("Contents",typeof(String))
                              };
            tb.Columns.AddRange(cols);

            string contents = String.Empty;
            for (int i = 1; i <= 50; i++)
                contents += "Why Vertical Scroll lagging in wrapmode true? ";

            for (int i = 1; i <= 200; i++)
            {
                DataRow row = tb.NewRow();
                row["No"] = i.ToString();
                row["Contents"] = "★★★★★" +  contents;
                tb.Rows.Add(row);
            }
            
            

            dataGridView1.RowHeadersWidthSizeMode = DataGridViewRowHeadersWidthSizeMode.DisableResizing;
            dataGridView1.ColumnHeadersHeightSizeMode = DataGridViewColumnHeadersHeightSizeMode.DisableResizing;
            dataGridView1.ColumnHeadersHeight = 30;
            dataGridView1.ColumnHeadersDefaultCellStyle.Alignment = DataGridViewContentAlignment.MiddleCenter;
            dataGridView1.RowHeadersVisible = false;

            dataGridView1.AllowUserToAddRows = false;
            dataGridView1.AllowUserToDeleteRows = false;
            dataGridView1.AllowUserToResizeRows = false;
            dataGridView1.AllowUserToResizeColumns = false;
            dataGridView1.EditMode = DataGridViewEditMode.EditProgrammatically;

            SendMessage(dataGridView1.Handle, WM_SETREDRAW, false, 0);

            dataGridView1.DataSource = tb;

            dataGridView1.Columns["Contents"].Width = 650; //Contents
            dataGridView1.Columns["Contents"].DefaultCellStyle.WrapMode = DataGridViewTriState.True; // *****
            dataGridView1.AutoSizeRowsMode = DataGridViewAutoSizeRowsMode.None; //*****
            dataGridView1.AutoResizeRows(DataGridViewAutoSizeRowsMode.AllCells); //****

            SendMessage(dataGridView1.Handle, WM_SETREDRAW, true, 0);
        }
    }
    public class DataGridViewDoubleBuffered : DataGridView
    {
        public DataGridViewDoubleBuffered()
        {
            DoubleBuffered = true;
        }
    }
}

Answer 1

Hi greinke21,
You can autosize the rows by using the following code

dataGridView1.AutoSizeRowsMode = DataGridViewAutoSizeRowsMode.DisplayedCells;

instead of DataGridViewAutoSizeRowsMode.AllCells.
Here is a similar thread you can refer to.
Best Regards,
Daniel Zhang

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Answer 2

Thanks for the answer
dataGridView1.AutoSizeRowsMode = DataGridViewAutoSizeRowsMode.DisplayedCells;
If I set this, only the screen shown is multiline text, and scrolling down does not adjust the row height, so the multiline text is not visible.
I tried connecting to the datagridview scroll event according to the answer link, but the scrolling behavior is abnormal.

Answer 3

Hello,

An alternate idea is to use a TextBox bound to the column currently used in the DataGridView e.g.

contentTextBox.DataBindings.Add("Text", tb, "Contents");

Also, on a side note I recommend using a BindingSource as this permits getting to your data without accessing the actual DataGridView e.g..

private BindingSource _bindingSource = new BindingSource();

...

_bindingSource.DataSource = tb;

...

Later we can use

var currentRow = ((DataRowView) _bindingSource.Current).Row;

To a column value

var contents = currentRow.Field<string>("Contents");

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