问题
I am loading data from two tables: institute and country. Institute has 3 columns: instId, name, countryId. And country has 2 columns: countryId, name where countryId is a foreign key from country table. I fill these two tables in dataset. I have datagridview and set its datasource to institute table in my dataset. I also create datagridviewcomboboxcolumn and bind it country table. Have a look to the following code:
Public Class frmDGV
Dim sqlConn As SqlConnection
Dim dsOptions As DataSet
Dim daInstitute As SqlDataAdapter
Dim daAdapter As SqlDataAdapter
Dim bsCountry As BindingSource
Private Sub frmTest_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Try
dsOptions = New DataSet
loadOptions()
dgvInstitute.DataSource = dsOptions.Tables("institute")
bsCountry = New BindingSource(dsOptions, "country")
Dim col As New DataGridViewComboBoxColumn
col.DataPropertyName = "countryName"
col.HeaderText = "Country"
col.Name = "cName"
col.DataSource = bsCountry
col.DisplayMember = "countryName"
col.ValueMember = "countryId"
dgvInstitute.Columns.Add(col)
dgvInstitute.Columns(0).Width = 60
dgvInstitute.Columns(1).Width = 200
dgvInstitute.Columns(2).Width = 60
dgvInstitute.Columns(3).Width = 120
Catch ex As Exception
MsgBox(Err.Description)
End Try
End Sub
Sub loadOptions()
Dim sql As String
Try
sqlConn = New SqlConnection(connString)
sqlConn.Open()
sql = "select instId, name, countryId from institute"
daInstitute = New SqlDataAdapter(sql, sqlConn)
daInstitute.Fill(dsOptions, "institute")
'----------------------------------------------------------------------
sql = "select countryId, countryName from country"
daAdapter = New SqlDataAdapter(sql, sqlConn)
daAdapter.Fill(dsOptions, "country")
'----------------------------------------------------------------------
sqlConn.Close()
Catch ex As Exception
sqlConn.Close()
MsgBox(Err.Description)
End Try
End Sub
End Class
How can I display the proper country name in the combobox based on the countryId in the datagridview using the binding techniques not using a loop? See the following picture:
回答1:
Change DataPropertyName for comboboxcolumn in your datagridview:
...
col.DataPropertyName = "countryId"
...
.DataPropertyName - is a column name from datagridview.DataSource,which you want to show in the current column.
回答2:
To be honest im not sure if you can due to the way you have bound this.
Does the country column need to be in a ComboBox? You could just include the country name in your first query.
The only way i could really see of doing this would be something like
for(int i = 0; i<dgvInstitute.Rows.Count; i++)
{
dgvInstitute.Rows[rowIndexYouWant].Cells["cName"].Value = dgvInstitute.Rows[rowIndexYouWant].Cells["countryId"].Value;
}
回答3:
Imports System.Data.SqlClient
Imports System.Data
Public Class DataGridViewBind
Private Sub DataGridViewBind_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'Preparing The Column
Dim col0 As New DataGridViewTextBoxColumn
col0.HeaderText = "InstID"
col0.Name = "InstID"
col0.Width = 100
col0.MaxInputLength = 100
dgv1.Columns.Add(col0)
Dim col1 As New DataGridViewTextBoxColumn
col1.HeaderText = "Name"
col1.Name = "Name"
col1.Width = 100
col1.MaxInputLength = 100
dgv1.Columns.Add(col1)
Dim col2 As New DataGridViewTextBoxColumn
col2.HeaderText = "CountryID"
col2.Name = "CountryID"
col2.Width = 100
col2.MaxInputLength = 100
dgv1.Columns.Add(col2)
Dim Col3 As New DataGridViewComboBoxColumn
Col3.HeaderText = "CountryName"
Col3.Name = "CountryName"
Col3.Width = 100
ProcessCountryComboBox(Col3) 'Bind Country Name to the ComboBox
dgv1.Columns.Add(Col3)
'Prepare the DataGridView
ListDataGridView(dgv1)
End Sub
Public Sub ProcessCountryComboBox(ByVal colX As DataGridViewComboBoxColumn)
Dim StrConn As String = My.Settings.ImportLinkCS
Dim CN = New SqlConnection(StrConn)
LoadGridComboByQuery(colX, "Select Name from Country order by Name")
End Sub
Public Sub LoadGridComboByQuery(ByVal cbo As DataGridViewComboBoxColumn, ByVal SQLString As String)
Dim i As Integer
Dim cmdUser As New SqlCommand
Dim daUser As New SqlDataAdapter
Dim dsUser As New DataSet
Dim dtUser As New DataTable
Dim conn As New SqlConnection(My.Settings.ImportLinkCS)
Try
cbo.Items.Clear()
cmdUser = conn.CreateCommand
cmdUser.CommandText = SQLString
daUser.SelectCommand = cmdUser
daUser.Fill(dsUser, "Sqltable")
dtUser = dsUser.Tables("Sqltable")
For i = 0 To dtUser.Rows.Count - 1
cbo.Items.Add(dtUser.Rows(i).Item(0))
Next
cbo.Items.Add("")
Catch ex As Exception
MsgBox("Error: " & ex.Source & ": " & ex.Message, MsgBoxStyle.OkOnly, "Error conection!!")
End Try
conn.Close()
conn = Nothing
End Sub
Private Sub ListDataGridView(ByVal dgv As DataGridView)
dgv.DataSource = Nothing
Try
Dim dbBindSource As New BindingSource
Dim strCon As String = My.Settings.ImportLinkCS
Dim strSQL As String = "Select I.InstID, I.Name, I.Country, C.Name as CountryName " + _
"from Institute I left Join Country C on C.CountryID = I.Country"
Dim dataAdapter As SqlDataAdapter = New SqlDataAdapter(strSQL, strCon)
Dim commandBuilder As SqlCommandBuilder = New SqlCommandBuilder(dataAdapter)
'Populate a new data table and bind it to the BindingSource.
Dim table As DataTable = New DataTable()
table.Locale = System.Globalization.CultureInfo.InvariantCulture
dataAdapter.Fill(table)
dgv.AutoGenerateColumns = False
dgv.Columns(0).DataPropertyName = "InstID"
dgv.Columns(1).DataPropertyName = "Name"
dgv.Columns(2).DataPropertyName = "Country"
dgv.Columns(3).DataPropertyName = "CountryName"
dbBindSource.DataSource = table
//Resize the DataGridView columns to fit the newly loaded content.
//dgv.AutoResizeColumns(DataGridViewAutoSizeColumnsMode.AllCellsExceptHeader)
dgv.DataSource = dbBindSource
Catch ex As Exception
MsgBox(ex.Message, MsgBoxStyle.Critical, "error")
End Try
End Sub
End Class
来源：https://stackoverflow.com/questions/21084106/vb-net-binding-datagridview-comboboxcolumn-to-datagridviewtextboxcolumn