为什么要使用row.Cells[row.Index]。需要指定要搜索的列的索引（问题2）。例如，需要将row.Cells[row.Index]更改为row.Cells[2]，其中2是列的索引：

private void btnSearch_Click(object sender, EventArgs e)
{
    string searchValue = textBox1.Text;

    dgvProjects.SelectionMode = DataGridViewSelectionMode.FullRowSelect;
    try
    {
        foreach (DataGridViewRow row in dgvProjects.Rows)
        {
            if (row.Cells[2].Value.ToString().Equals(searchValue))
            {
                row.Selected = true;
                break;
            }
        }
    }
    catch (Exception exc)
    {
        MessageBox.Show(exc.Message);
    }
}

为什么不先构建一个DataTable，然后将其作为DataSource分配给DataGridView：

DataTable table4DataSource=new DataTable();

table4DataSource.Columns.Add("col00");
table4DataSource.Columns.Add("col01");
table4DataSource.Columns.Add("col02");

...

(add您的行，手动，在一个圆圈中或通过数据库表中的DataReader）（分配数据源）

dtGrdViewGrid.DataSource = table4DataSource;

然后用途：

(dtGrdViewGrid.DataSource as DataTable).DefaultView.RowFilter = "col00 = '" + textBoxSearch.Text+ "'";
dtGrdViewGrid.Refresh();

您甚至可以将这段代码放在您的textbox_textchange事件中，您的过滤值将在您编写时显示。

最好将逻辑分离到另一个方法中，或者另一个类中。
此方法将帮助您检索在其中找到文本的DataGridViewCell对象。

/// <summary>
    /// Check if a given text exists in the given DataGridView at a given column index
    /// </summary>
    /// <param name="searchText"></param>
    /// <param name="dataGridView"></param>
    /// <param name="columnIndex"></param>
    /// <returns>The cell in which the searchText was found</returns>
    private DataGridViewCell GetCellWhereTextExistsInGridView(string searchText, DataGridView dataGridView, int columnIndex)
    {
        DataGridViewCell cellWhereTextIsMet = null;

        // For every row in the grid (obviously)
        foreach (DataGridViewRow row in dataGridView.Rows)
        {
            // I did not test this case, but cell.Value is an object, and objects can be null
            // So check if the cell is null before using .ToString()
            if (row.Cells[columnIndex].Value != null && searchText == row.Cells[columnIndex].Value.ToString())
            {
                // the searchText is equals to the text in this cell.
                cellWhereTextIsMet = row.Cells[columnIndex];
                break;
            }
        }

        return cellWhereTextIsMet;
    }

    private void button_click(object sender, EventArgs e)
    {
        DataGridViewCell cell = GetCellWhereTextExistsInGridView(textBox1.Text, myGridView, 2);
        if (cell != null)
        {
            // Value exists in the grid
            // you can do extra stuff on the cell
            cell.Style = new DataGridViewCellStyle { ForeColor = Color.Red };
        }
        else
        {
            // Value does not exist in the grid
        }
    }

//     This is the exact code for search facility in datagridview.
private void buttonSearch_Click(object sender, EventArgs e)
{
    string searchValue=textBoxSearch.Text;
    int rowIndex = 1;  //this one is depending on the position of cell or column
    //string first_row_data=dataGridView1.Rows[0].Cells[0].Value.ToString() ;

    dataGridView1.SelectionMode = DataGridViewSelectionMode.FullRowSelect;
    try
    {
        bool valueResulet = true;
        foreach (DataGridViewRow row in dataGridView1.Rows)
        {
            if (row.Cells[rowIndex].Value.ToString().Equals(searchValue))
            {
                rowIndex = row.Index;
                dataGridView1.Rows[rowIndex].Selected = true;
                rowIndex++;
                valueResulet = false;
            }
        }
        if (valueResulet != false)
        {
            MessageBox.Show("Record is not avalable for this Name"+textBoxSearch.Text,"Not Found");
            return;
        }
    }
    catch (Exception exc)
    {
        MessageBox.Show(exc.Message);
    }
}

直接从DataTable或Dataset筛选数据：

"MyTable".DefaultView.RowFilter = "<DataTable Field> LIKE '%" + textBox1.Text + "%'";
   this.dataGridView1.DataSource = "MyTable".DefaultView;

在Textbox的事件KeyUp上使用此代码，将“MyTable”替换为表名或数据集，将“MyTable”替换为要进行搜索的字段。

“我的表”。默认视图。行筛选器=“LIKE '%”+文本框1.Text+“%'”;数据源=“我的表”.默认视图;
数据库连接和数据表的关系如何？我应该如何正确设置DefaultView？
我用下面的代码来获取数据：

con = new System.Data.SqlServerCe.SqlCeConnection();
con.ConnectionString = "Data Source=C:\\Users\\mhadj\\Documents\\Visual Studio 2015\\Projects\\data_base_test_2\\Sample.sdf";
con.Open();

DataTable dt = new DataTable();

adapt = new System.Data.SqlServerCe.SqlCeDataAdapter("select * from tbl_Record", con);        
adapt.Fill(dt);        
dataGridView1.DataSource = dt;
con.Close();

private void btnSearch_Click(object sender, EventArgs e)
    {
        try
        {
            string searchValue = txtSearch.Text;
            string colName = dataGridView1.Columns[1].Name;//Column Number of Search
            ((DataTable)dataGridView1.DataSource).DefaultView.RowFilter = string.Format(colName+" like '%{0}%'", searchValue.Trim().Replace("'", "''"));
        }
        catch (Exception exc)
        {
            MessageBox.Show(exc.Message);
        }
      
    }

    private void txtSearch_TextChanged(object sender, EventArgs e)
    {
        btnSearch_Click(null,null);
    }

private void txtSearch_TextChanged(object sender, EventArgs e)
{
     string searchValue = txtSearch.Text;
     for (var i = 0; i <= dgvList.RowCount; i++)
     {
          for (var j = 0; j <= dgvList.ColumnCount; j++)
          {
               if ((dgvList.Item(j, i).FormattedValue.ToString.ToLower).ToString.Contains(searchValue.ToString.ToLower))
               {
                    Console.Writeline("found");
                    dgvList.Item(j, i).Selected = true;
                    return;
               }
          }
     }
     
}

此方法将搜索DataGridView中的所有行和单元格，如果结果为true，则选择该行。

我很可以简单地解决它：

public static int SearchDGV(DataGridView dgv, string SearchValue, string ColName)
    {
        foreach (DataGridViewRow Row in dgv.Rows)
        {
            if (Row.Cells[ColName].Value.ToString().Equals(SearchValue))
                return Row.Index;
        }
        return -1;
    }