Question

我是EF的新手。当我们使用datareader或数据集时，我们有时会在循环中填充控件的值。喜欢

  datareader dr=getdata()
  while(dr.read())
  {
    // in this loop we can populate control with value from datareader 
  }

  dataset ds =getdata()
  for(int i=0;i<=ds.tables[0].rows.count-1;i++)
  {
    // in this loop we can populate control with value from dataset
  }

所以我只想知道我何时使用EF然后如何迭代循环并使用值填充控件。

另一个问题是如何在EF中取消null。

请帮我提供示例代码以了解相关内容。感谢

Answer 1

这是一个人为的代码示例，展示如何实现您的需求。

// Get all the cars
List<Car> cars = context.Cars.ToList();

// Clear the DataViewGrid
uiGrid.Rows.Clear();

// Populate the grid
foreach (Car car in cars)
{
    // Add a new row
    int rowIndex = uiGrid.Rows.Add();
    DataGridViewRow newRow = uiGrid.Rows[rowIndex];

    // Populate the cells with data for this car
    newRow.Cells["Make"].Value = car.Make;
    newRow.Cells["Model"].Value = car.Model;
    newRow.Cells["Description"].Value = car.Description;

    // If the price is not null then add it to the price column
    if (car.Price != null)
    {
        newRow.Cells["Price"].Value = car.Price;
    }
    else
    {
        newRow.Cells["Price"].Value = "No Price Available";
    }
}

Answer 2

这会有所帮助：

http://www.datasprings.com/resources/articles-information/a-quick-guide-to-using-entity-framework

实体框架数据绑定通过循环

2 个答案: