显示数据表的一列值的总和 [英] Show total Sum of values of a Column of a DataTable

问题描述

我想显示商品总价的总和.我面临两个问题:

I want to show sum of total Price of items. I am facing 2 issues:

• 它向我显示了错误的商品总价
• 我想将 .00 添加到总价中

• It's showing me wrong total of items price
• I want to add .00 to the total price

您可以在图片中查看问题以获得清晰的解释.

You can check issue in the image for a clear explanation.

这是我的代码:

tDisplay.Text = "Return/" + "Receipt No:" + Return_Form.setalueforText011;
label1.Text = Return_Form.setalueforText011;

OleDbConnection VCON = new OleDbConnection(@"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=D:Restaurant.accdb");
DataSet dsa = new DataSet();
DataTable dt = new DataTable();
dsa.Tables.Add(dt);

OleDbDataAdapter da = new OleDbDataAdapter();
da = new OleDbDataAdapter("SELECT [Column1],[Column2],[Column3] from [Total] Where [Receipt No] =  " + label1.Text + "", VCON);
da.Fill(dt);
//dataGridView1.DataSource = dt;

for (int i = 0; i < dt.Rows.Count; i++)
{
    products.Add(new tblProduct() { productName = dt.Rows[i]["Column2"].ToString(),productPrice = Convert.ToDecimal(Math.Round(Convert.ToDecimal(dt.Rows[i]["Column1"].ToString())))});
    label3.Text = dt.Rows[i]["Column3"].ToString();
    textBox59.Text = "Rs: "+String.Format("{0:}", Total);
    tblProduct selected = (tblProduct)(listBox60.SelectedItem);
    Total += (decimal)selected.productPrice;
}
VCON.Close();

推荐答案

Sum

您可以简单地使用 Compute 数据表的方法并传递表达式进行计算.例如:

Instead of using for loop, You can simply use Compute method of data table and pass an expression to compute. For example:

var total = yourDataTable.Compute("SUM(Column1)", "");

格式

还要格式化总计以在小数点后显示 2 位数字，您可以使用以下任一选项:

Also to format total to show 2 digits after decimal place, you can use either of these options:

• 0" 自定义数字格式字符串 : string.Format("{0:0.00}", total))

固定-点F"格式说明符:string.Format("{0:F2}", total))

更新数据变化的总和

还可以在添加新项目或删除某些项目或更改某些值时在 TextBox 事件中自动显示总和，处理 的 ListChanged 事件DataTable.DefaultView 并将结果设置为文本框的Text.

Also to be able to show the sum automatically in a TextBox event when new items added or some items removed or some values changed, handle ListChanged event of DataTable.DefaultView and set the result as Text of the text box.

// Define data table
var dt = new DataTable();
dt.Columns.Add("Name");
dt.Columns.Add("Price", typeof(int));

// Fill data
dt.Rows.Add("Product 1", 100);
dt.Rows.Add("Product 2", 200);

// Set data source of data grid view
this.dataGridView1.DataSource = dt;

// Automatically update text box, by SUM of price
textBox1.Text = $"{dt.Compute("SUM(Price)", ""):F2}";
dt.DefaultView.ListChanged += (obj, args) =>
    textBox1.Text = $"{dt.Compute("SUM(Price)", ""):F2}";

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