How do I get my data to show in correct DataGridView column?

I am trying to populate my DataGridView with custom columns imported from Excel. This should be easy but for the life of me, I am stuck in a brainlock. I should be able to select the specific columns (works), send the column headers to my excel class to parse the data from that column (works), send the parsed data to a List (works) and then import the data to the datagridview by setting my DataSource as my List (I am creating the column header text, but the code is creating a column called Value and adding my data to it). Here is my code that is creating the problem:

private void btnCreateTable_Click(object sender, EventArgs e)
    {
        List<StringValue>[] listArr = new List<StringValue>[columnCount];
        ExcelClass getData = new ExcelClass();
        tabControl1.SelectedTab = tabDataTable;
        dgv.Visible = true;
        
        DataGridViewTextBoxColumn t = new DataGridViewTextBoxColumn();

        //dgvSelectedHeaders.Columns[i].Name = selectedHeaders[i];
        for (int i = 0; i < columnCo开发者_运维知识库unt; i++)
        {
            //dgv[i].DataSource = getData.GetDataFromExcel(headersArr[i], path);
            listArr[i] = getData.GetDataFromExcel(selectedHeaders[i], path);
            t.Name = selectedHeaders[i];
            t.HeaderText = selectedHeaders[i];
            dgv.Columns.Add(t);
            dgv.DataMember = "String";
            dgv.DataSource = listArr[i];
            for (int j = 0; j < getData.RowCount; j++)
            {
                dgv.Rows.Add();
                for (int k = 0; k < getData.RowCount; k++)
                {
                    dgv[k, j].Value = listArr[j][k].ToString();
                }
            }

        }

If I select more than one column, it shows the first one but I get an error after the first one at row dgv.Columns.Add(t); ... InvalidOperationException, provided column already belongs to the DataGridView control... I know these are two questions, but I think they are tied together somehow.

Thanks in advance, and if you need more code, let me know.

I think you need to create a new DataGridViewColoumn for each column

for (int i = 0; i < columnCount; i++) 
{
    DataGridViewTextBoxColumn t = new DataGridViewTextBoxColumn(); 
    // ...
    dgv.Columns.Add(t);
}

rather than reusing it.