Datagridview rowvalidating delete
event, which enables the control look up values in the data cache.Virtual mode is necessary only when you need to supplement or replace bound mode.Call the Update Row Height Info method when changing the cached row height information outside of a Row Height Info Pushed event handler to ensure that the current value is used in the display of the control.If you are implementing virtual mode in order to work efficiently with large amounts of data, you will also want to ensure that you are working efficiently with the Data Grid View control itself.You can also handle events that let you maintain values not typically stored in a bound data source, such as cell Tool Tip text, cell and row error text, cell and row shortcut menu data, and row height data.For more information about implementing virtual mode to manage read/write data with a row-level commit scope, see Walkthrough: Implementing Virtual Mode in the Windows Forms Data Grid View Control.Because unbound columns are outside the data source, they are ignored by the data source's sorting operations. Data Grid View Combo Box Column class reference topics.Therefore, when you enable sorting in mixed mode, you must manage the unbound data in a local cache and implement virtual mode to let the Data Grid View control interact with it. If bound mode does not meet your performance needs, you can manage all your data in a custom cache through virtual-mode event handlers.
You can customize sizing behaviors when working with derived Data Grid View cell, row, and column types by overriding the Data Grid View Cell. The protected resizing method overloads are designed to work in pairs to achieve an ideal cell height-to-width ratio, avoiding overly wide or tall cells.
For all sizing enumerations, values with names that refer to displayed cells limit their calculations to cells in displayed rows.
With these values, you can limit which cells are used to calculate the preferred sizes.
For example, you might programmatically resize all columns immediately after loading data, or you might programmatically resize a specific row after a particular cell value has been modified. Get Preferred Width() methods or by calling protected resizing method overloads in a derived Data Grid View control.
You will typically call the programmatic resizing methods at specific times.