c# datadridview

Question

C# I want to increase the value of the selected cell with (+) and (-) buttons.

Answer 1

Best way to do this is have a DataSource e.g. in this case a DataTable. In the code below I increase and decrease the Qty value of the current row in the DataGridView.

The BindingSource component provides access to the current row, we cast to a DataRow than use SetField and Field extensions to change values.

Alternate to a DataTable would be a List<T>

namespace DataGridViewDemo  
{  
    public partial class DataGridViewForm : Form  
    {  
        private BindingSource bindingSource = new BindingSource();  
        public DataGridViewForm()  
        {  
            InitializeComponent();  
  
            Shown += OnShown;  
  
        }  
  
        private void OnShown(object sender, EventArgs e)  
        {  
              
            dataGridView1.AutoGenerateColumns = false;  
  
            DataTable table = new DataTable();  
            table.Columns.Add("Item", typeof(string));  
            table.Columns.Add("Qty", typeof(int));  
            table.Columns.Add("Price", typeof(decimal));  
  
            table.Rows.Add("First item", 2, 60);  
            table.Rows.Add("Second item", 2, 50);  
            table.Rows.Add("Third item", 1, 20);  
  
            bindingSource.DataSource = table;  
            dataGridView1.DataSource = bindingSource;  
  
        }  
  
        private void IncreaseButton_Click(object sender, EventArgs e)  
        {  
            var row = ((DataRowView)bindingSource.Current).Row;  
            row.SetField("Qty", row.Field<int>("Qty") +1);  
        }  
  
        private void DecreaseButton_Click(object sender, EventArgs e)  
        {  
            var row = ((DataRowView)bindingSource.Current).Row;  
            row.SetField("Qty", row.Field<int>("Qty") -1);  
  
        }  
    }  
}  

Source code

Can be found here.

Answer 2

I'm sorry I don't know much, but I can't increase or decrease it again.

using System;  
using System.Collections.Generic;  
using System.ComponentModel;  
using System.Data;  
using System.Drawing;  
using System.Linq;  
using System.Text;  
using System.Threading.Tasks;  
using System.Windows.Forms;  
using System.Data.SqlClient;  
  
namespace kafe_ders  
{  
    public partial class Form2 : Form  
    {  
  
        SqlConnection connection = new SqlConnection("Data Source=DESKTOP-46FHV6F;Initial Catalog=ders-kafe;Integrated Security=True");  
        SqlCommandBuilder commandBuilder ;  
        SqlDataAdapter adtr;  
        DataTable tbl= new DataTable();  
          
        public Form2()  
        {  
            InitializeComponent();  
            GetList();  
              
  
            Shown += OnShown;  
        }    
        DataTable GetList()  
        {  
            tbl.Clear();  
            adtr = new SqlDataAdapter("select * from musteri",connection);  
            adtr.Fill(tbl);  
            dataGridView1.DataSource = tbl;  
            return tbl;  
        }  
        private void Form2_Load(object sender, EventArgs e)  
        {  
            // TODO: Bu kod satırı '_ders_kafeDataSet12.musteri' tablosuna veri yükler. Bunu gerektiği şekilde taşıyabilir, veya kaldırabilirsiniz.  
            this.musteriTableAdapter2.Fill(this._ders_kafeDataSet12.musteri);  
        }  
        private void button2_Click(object sender, EventArgs e)  
        {  
            commandBuilder = new SqlCommandBuilder(adtr);  
            adtr.Update(tbl);  
            GetList();  
        }  
  
        private void button4_Click(object sender, EventArgs e)  
        {  
              
            this.Close();  
        }  
        private void selectedCellsButton_Click(object sender, System.EventArgs e)  
        {  
            Int32 selectedCellCount =  
                dataGridView1.GetCellCount(DataGridViewElementStates.Selected);  
            if (selectedCellCount > 0)  
            {  
                if (dataGridView1.AreAllCellsSelected(true))  
                {  
                    MessageBox.Show("All cells are selected", "Selected Cells");  
                }  
                else  
                {  
                    System.Text.StringBuilder sb =  
                        new System.Text.StringBuilder();  
  
                    for (int i = 0;  
                        i < selectedCellCount; i++)  
                    {  
                        sb.Append("Row: ");  
                        sb.Append(dataGridView1.SelectedCells[i].RowIndex  
                            .ToString());  
                        sb.Append(", Column: ");  
                        sb.Append(dataGridView1.SelectedCells[i].ColumnIndex  
                            .ToString());  
                        sb.Append(Environment.NewLine);  
                    }  
  
                    sb.Append("Total: " + selectedCellCount.ToString());  
                    MessageBox.Show(sb.ToString(), "Selected Cells");  
                }  
            }  
        }  
        int deger ;  
        private void dataGridView1_CellMouseClick_1(object sender, DataGridViewCellEventArgs e)  
        {  
  
        }  
        private BindingSource bindingSource = new BindingSource();  
        private void OnShown(object sender, EventArgs e)  
        {  
  
            dataGridView1.AutoGenerateColumns = false;  
  
            DataTable table = new DataTable();  
            table.Columns.Add("Item", typeof(string));  
            table.Columns.Add("Qty", typeof(int));  
            table.Columns.Add("Price", typeof(decimal));  
  
            table.Rows.Add("First item", 2, 60);  
            table.Rows.Add("Second item", 2, 50);  
            table.Rows.Add("Third item", 1, 20);  
  
            bindingSource.DataSource = table;  
            dataGridView1.DataSource = bindingSource;  
        }  
        private void button1_Click_1(object sender, EventArgs e)  
        {  
            var row = ((DataRowView)bindingSource.Current).Row;  
            row.SetField("Qty", row.Field<int>("Qty") + 1);  
        }  
        private void button3_Click(object sender, EventArgs e)  
        {  
            var row = ((DataRowView)bindingSource.Current).Row;  
            row.SetField("Qty", row.Field<int>("Qty") - 1);  
        }  
    }  
}