How to clear a data grid view

Question

I am trying to populate a DataGridView based on the selected item in a ComboBox  I have this part working   However  I need to be able to clear the grid before adding the new data from a new item rather than it just adding on to the end    How do I clear a DataGridView before adding items to it

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Solution is   while  dataGridView1 RowCount  gt  1        dataGridView1 Rows RemoveAt 0

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If you want to clear all the headers as well as the data  for example if you are switching between 2 totally different databases with different fields  therefore different columns and column headers  I found the following to work  Otherwise when you switch you have the columns  fields from both databases showing in the grid   dataTable Dispose     get rid of existing datatable dataTable   new DataTable     create new datatable  datagrid DataSource   dataTable   clears out the datagrid with empty datatable   datagrid Refresh    This does not seem to be neccesary  dataadapter Fill dataTable     assumming you set the adapter with new data                datagrid DataSource   dataTable

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You can assign the datasource as null of your data grid and then rebind it   dg DataSource   null  dg DataBind

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If it s bound to a datasource -  dataGridView DataSource null  dataGridView Rows Clear      Worked for me

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private void ClearGrid             if this InvokeRequired  this Invoke new Action this ClearGrid         this dataGridView DataSource   null      this dataGridView Rows Clear        this dataGridView Refresh

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You can clear DataGridView in this manner      dataGridView1 Rows Clear    dataGridView1 Refresh      If it is databound then try this  dataGridView1 Rows Clear      If dgv is bound to datatable dataGridView1 DataBind

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Firstly  null the data source   this dataGridView DataSource   null    Then clear the rows   this dataGridView Rows Clear      Then set the data source to the new list   this dataGridView DataSource   this GetNewValues

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YourGrid Items Clear    YourGrid Items Refresh

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IF you want to clear not only Data  but also ComboBoxes  Checkboxes  try  dataGridView Columns Clear

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You could take this next instruction and would do the work with lack of perfomance  If you want to see the effect of that  put one of the 2 next instructions  Technically similars  where you need to clear the DataGridView into a try   catch        finally block and wait what occurs        while  dataGridView1 Rows Count  gt  1                dataGridView1 Rows RemoveAt 0              foreach  object  Cols in dataGridView1 Columns                dataGridView1 Columns RemoveAt 0           You improve this task but its not enough  there is a problem to reset a DataGridView  because of the colums that remains in the DataGridView object  Finally I suggest  the best way i ve implemented in my home practice is to handle this gridView as a file with rows  columns  a record collection based on the match between rows and columns  If you can improve  then take your own choice a  or b   foreach or while           a   With foreach      foreach  object  Cols in dataGridView1 Columns                dataGridView1 Columns RemoveAt 0              foreach object  row in dataGridView1 Rows           dataGridView1 Rows RemoveAt 0                 b   With foreach      while  dataGridView1 Rows Count  gt  1                dataGridView1 Rows RemoveAt 0             while  dataGridView1 Columns Count  gt  0                dataGridView1 Columns RemoveAt 0           Well  as a recomendation Never in your life delete the columns first  the order is before the rows after the cols  because logically the columns where created first and then the rows It would be a penalty in terms of correct analisys        foreach  object  Cols in dataGridView1 Columns                dataGridView1 Columns RemoveAt 0             foreach  object  row in dataGridView1 Rows                dataGridView1 Rows RemoveAt 0             while  dataGridView1 Rows Count  gt  1                dataGridView1 Rows RemoveAt 0              while  dataGridView1 Columns Count  gt  0                dataGridView1 Columns RemoveAt 0           Then  Put it inside a function or method    private void ClearDataGridViewLoopWhile                    while  dataGridView1 Rows Count  gt  1                dataGridView1 Rows RemoveAt 0              while  dataGridView1 Columns Count  gt  0                dataGridView1 Columns RemoveAt 0            private void ClearDataGridViewForEach         foreach  object  Cols in dataGridView1 Columns                dataGridView1 Columns RemoveAt 0             foreach  object  row in dataGridView1 Rows                dataGridView1 Rows RemoveAt 0             Finally  call your new function ClearDataGridViewLoopWhile    or ClearDataGridViewForEach    where you need to use it  but its recomended when you are making queries and changing over severall tables that will load with diferents header names in the grieView  But if you want preserve headers here there is a solution given

User · Answer

The solution is   dataGridView1 Rows RemoveAt 0     Clears the grid and preserves the columns

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This is working to me   int numRows   dgbDatos Rows Count               for  int i   0  i  lt  numRows  i                                  try                                        int max   dgbDatos Rows Count - 1                      dgbDatos Rows Remove dgbDatos Rows max                        btnAgregar Enabled   true                                    catch  Exception exe                                        MessageBox Show  No se puede eliminar     exe                          MessageBoxButtons OK  MessageBoxIcon Information

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For having a Datagrid you must have a method which is formatting your Datagrid  If you want clear the Datagrid you just recall the method   Here is my method       public string   dgv Headers   new string      Id   Hotel    Lunch    Dinner    Excursions    Guide    Bus        This defined at Public partial class       private void SetDgvHeader                 dgv Rows Clear            dgv ColumnCount   7          dgv RowHeadersVisible   false          int Nbr   int Parse daysBox Text       in my method it s the textbox where i keep the number of rows I have to use         dgv Rows Add Nbr           for int i  0  i lt Nbr   i              dgv Rows i  Height   20          for  int i   0  i  lt  dgv Headers Length    i                        if i  0                  dgv Columns i  Visible   false      I need an invisible cells if you don t need you can skip it             else                 dgv Columns i  Width   78              dgv Columns i  HeaderText   dgv Headers i                     dgv Height    Nbr  dgv Rows 0  Height    35          dgv AllowUserToAddRows   false          dgv is the name of DataGridView

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DataGrid DataSource   null  DataGrid DataBind

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dataGridView1 Rows Clear    dataGridView1 Refresh

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refresh the datagridview and refresh the datatable  dataGridView1 Refresh    datatable Clear

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datatable Clear    dataGridView1 DataSource   datatable

[c#] How to clear a data grid view

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